ALP2-D-40 Marzocchi Gear Pump 28.2cc 170 bar 1800 rpm

Product Overview

The ALP2-D-40, ALP2A-D-34-FG, ALP2A-D-40-FG, 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 mounting flange configuration.

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

• Maximum Speed Range: 1800 – 4000 rpm (displacement-dependent)

• Minimum Speed: 500 – 800 rpm

• Maximum Continuous Pressure (P1): 140 – 250 bar (displacement-dependent)

• Maximum Intermittent Pressure (P2): 155 – 270 bar

• Maximum Peak Pressure (P3): 170 – 290 bar

• 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

• Maximum Input Torque: 100 Nm

• Operating Temperature Range: -10°C to +120°C (with relief valve: max +80°C)

ALP2-D-40 / ALP2A-D-40-FG

• Displacement: 28.2 cm³/rev

• Flow Rate (@1500 rpm): 40.1 – 42.3 L/min

• Maximum Continuous Pressure (P1): 170 bar

• Maximum Intermittent Pressure (P2): 185 bar

• Maximum Peak Pressure (P3): 200 bar

• Maximum Speed: 1800 – 2600 rpm

• Net Weight: 3.3 kg

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: 2000 – 3000 rpm

• Net Weight: 3.2 kg

ALP2-D-16-FG

• Displacement: 11.5 cm³/rev

• Rated Flow: 16 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: 2.7 kg

ALP2-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: 3200 – 4000 rpm

• Net Weight: 2.8 kg

ALP2-D-22-FG

• Displacement: 16.0 cm³/rev

• Maximum Continuous Pressure (P1): 210 bar

• Maximum Intermittent Pressure (P2): 225 bar

• Maximum Peak Pressure (P3): 240 bar

• Maximum Speed: 2800 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-40 weighs only 3.3 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

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

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

• Testing Machinery: Material testing machines, hydraulic test benches

• 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, 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.

2. Pre-Installation Checks

• Confirm pump rotation direction matches system drive direction. Reverse rotation is strictly prohibited.

• Check shaft type (tapered 1:8, keyed, or splined) precisely matches coupling.

• Confirm mounting flange is SAE A 2-bolt.

• 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

• Maintain fluid cleanliness within reasonable limits.

• Regularly monitor fluid cleanliness to prevent contaminants from accelerating gear and sliding bearing wear.

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.

• Maximum input torque must not exceed 100 Nm.