Product Overview
The ALP2-D-13, ALP2A-D-16, ALP2-D-20-EP, ALP2A-D-25-FG, as well as ALP2-D-34-FG, ALP2-D-16-FG, ALP2-D-20-FG, and ALP2-D-22-FG series gear pumps originate from Italy’s Marzocchi Pompe ALP2 Series high-performance external gear pump platform. Founded in 1961 and headquartered near Bologna, Italy, Marzocchi is a globally recognized manufacturer of gear pumps and gear motors.
The ALP2 Series is a Group 2 fixed-displacement external gear pump with displacements covering 4.5 to 35.2 cm³/rev. The pump body, flange, and cover are manufactured from special high-strength aluminum alloys that resist deformation even under high-pressure conditions. Gears are made from special steel, ground and fine-finished for an excellent surface profile, with optimized tooth profile design and geometric proportions ensuring low pulsation and low noise levels during operation.
The FG suffix indicates the model is equipped with an integral relief valve, providing system overload protection and simplifying external piping. ALP2A denotes standard SAE A mounting flange configuration. The EP suffix (e.g., ALP2-D-20-EP) indicates a special configuration version.
Key Interchangeability Advantage: Our ALP2 series gear pumps are manufactured to strict Italian Marzocchi original design specifications, ensuring 100% direct interchangeability with original units. All mounting interfaces (SAE A 2-bolt flange), drive shafts (tapered 1:8, splined, or keyed), and port configurations are identical to the original product. Every pump undergoes 100% factory performance testing under simulated operating conditions, guaranteeing plug-and-play reliability with zero performance deviation.
Technical Specifications
ALP2 Series – General Specifications
Product Series: ALP2 Series Fixed-Displacement External Gear Pump
Brand: Marzocchi Pompe (Italy)
Group: 2
Displacement Range: 4.5 – 35.2 cm³/rev
Operating Temperature Range: -10°C to +120°C (with relief valve: max +80°C)
Housing Material: Special high-strength aluminum alloy
Flange and Cover Material: Special high-strength aluminum alloy
Gear Material: Special ground and fine-finished steel
Bearing Type: Aluminum bushings (dual-sided)
Mounting Flange: SAE A 2-bolt
Mounting Torque: M10 bolts, 46 ± 4 Nm
ALP2-D-13 / ALP2A-D-13
Displacement: 9.6 cm³/rev
Flow Rate (@1500 rpm): 13.7 L/min
Maximum Continuous Pressure (P1): 250 bar
Maximum Intermittent Pressure (P2): 270 bar
Maximum Peak Pressure (P3): 290 bar
Maximum Speed: 4000 rpm
ALP2A-D-16 / ALP2-D-16-FG
Displacement: 11.5 cm³/rev
Flow Rate (@1500 rpm): 16.4 L/min
Maximum Continuous Pressure (P1): 230 bar
Maximum Intermittent Pressure (P2): 250 bar
Maximum Peak Pressure (P3): 270 bar
Maximum Speed: 4000 rpm
Net Weight: 2.6 kg
Inlet Port: #12 SAE (3/4″)
Outlet Port: #10 SAE (5/8″)
ALP2-D-20 / ALP2-D-20-EP / ALP2A-D-20-FG
Displacement: 14.1 cm³/rev
Flow Rate (@1500 rpm): 20.1 L/min
Maximum Continuous Pressure (P1): 230 bar
Maximum Intermittent Pressure (P2): 250 bar
Maximum Peak Pressure (P3): 270 bar
Maximum Speed: 4000 rpm
Net Weight: 2.85 kg
ALP2A-D-25-FG
Displacement: 17.9 cm³/rev
Flow Rate (@1500 rpm): 25.5 L/min
Maximum Continuous Pressure (P1): 210 bar
Maximum Intermittent Pressure (P2): 225 bar
Maximum Peak Pressure (P3): 240 bar
Maximum Speed: 2500 rpm
Net Weight: 2.9 kg
ALP2-D-22-FG
Displacement: 16.0 cm³/rev
Flow Rate (@1500 rpm): 22.8 L/min
Maximum Continuous Pressure (P1): 210 bar
Maximum Intermittent Pressure (P2): 225 bar
Maximum Peak Pressure (P3): 240 bar
Maximum Speed: 4000 rpm
ALP2-D-34-FG / ALP2A-D-34-FG
Displacement: 23.7 cm³/rev
Flow Rate (@1500 rpm): 33.7 L/min
Maximum Continuous Pressure (P1): 180 bar
Maximum Intermittent Pressure (P2): 195 bar
Maximum Peak Pressure (P3): 210 bar
Maximum Speed: 3000 rpm
Key Technical Advantages
1. Special High-Strength Aluminum Housing for Lightweight High Strength
The ALP2 Series pump body, flange, and cover are manufactured from special high-strength aluminum alloys that resist deformation even under high-pressure conditions. The lightweight design significantly reduces overall weight (ALP2-D-20 weighs only 2.85 kg, ALP2A-D-16 weighs only 2.6 kg), simplifying installation and maintenance.
2. Precision Ground Gears and Optimized Tooth Profile for Low Pulsation and Low Noise
Gears are manufactured from special steel with precision grinding and fine-finishing for an excellent surface profile. Optimized tooth profile design and geometric proportions ensure low pulsation and low noise levels during operation. Aluminum sliding bearings are coated with wear-resistant materials, further reducing maintenance requirements.
3. High Pressure Capacity
The ALP2 Series offers differentiated pressure ratings across displacement options. Small-displacement models (6–16 cm³/rev) deliver continuous pressure up to 250 bar and peak pressure up to 290 bar; mid-displacement models (20–25 cm³/rev) deliver 210–230 bar continuous; large-displacement models (30–50 cm³/rev) deliver 140–180 bar continuous. The broad pressure coverage ensures precise matching to diverse operating conditions.
4. Flexible Configuration Options and Integral Valve Functionality
The ALP2 Series supports multiple configuration options:
Mounting Flange: SAE A 2-bolt standard
Shaft Types: Tapered 1:8, keyed 5/8″, splined 9T 16/32DP
Port Connections: SAE flange or GAS thread
Integral Valve: FG suffix indicates integral relief valve for overload protection
5. Wide Displacement Coverage
The ALP2 Series offers 14 displacement options (6 / 9 / 10 / 12 / 13 / 16 / 20 / 22 / 25 / 30 / 34 / 37 / 40 / 50), covering 4.5 – 35.2 cm³/rev. The extensive selection ensures precise matching to diverse application requirements.
Application Areas
Construction Equipment: Mini excavators, wheel loaders hydraulic systems
Agricultural Machinery: Tractors, combine harvesters, sprayers hydraulic systems
Material Handling Equipment: Forklifts, stackers hydraulic systems
Industrial Machine Tools: Machine tool hydraulic transmission and control systems
Injection Molding Machinery: Injection molding machine auxiliary hydraulic systems
Presses and Stamping Equipment: Hydraulic presses, stamping equipment
Construction Machinery: Concrete pump trucks, mixer trucks hydraulic systems
Mobile Machinery: Various mobile equipment hydraulic systems
Expert Maintenance Tips
1. Model Confirmation and Selection
Complete ALP2 series model should include: Series + Displacement Code + D (clockwise)/S (counter-clockwise) + Configuration Suffix (FG with valve, A standard flange, EP special configuration, etc.).
FG suffix indicates integral relief valve – this valve is for overload protection only and must not be operated in continuous relief mode.
D indicates clockwise (right-hand) rotation; S indicates counter-clockwise (left-hand) rotation. Verify rotation direction based on original machine drive orientation.
ALP2A denotes standard SAE A mounting flange.
EP suffix indicates a special configuration version (e.g., ALP2-D-20-EP).
2. Pre-Installation Checks
Confirm pump rotation direction matches system drive direction. Reverse rotation is strictly prohibited.
Check shaft type (tapered 1:8, keyed 5/8″, or splined 9T 16/32DP) precisely matches coupling.
Confirm mounting flange is SAE A 2-bolt.
Mounting torque: M10 bolts, 46 ± 4 Nm.
Never use hammer-driven installation – always use proper tools.
3. First Start-Up & Oil Priming
Prime the pump housing with clean hydraulic oil before first start-up; ensure suction line is fully filled – never run dry.
Maintain operating oil temperature within -10°C to +120°C (with relief valve: max +80°C).
Minimum speed: 500 – 800 rpm.
4. Filtration & Fluid Cleanliness
5. Operating Monitoring
Continuous operating pressure must not exceed the P1 rating for each model.
If abnormal noise or pressure fluctuation occurs, first check suction lines for leakage or blockage.
Regularly check torque on pump and piping connection bolts to prevent loosening from vibration.
