Casappa AP300 Gear Pump Replacement | AP300/63 S 818

Genlu Hydraulic excels as an elite-tier global manufacturer of medium-to-high pressure external gear pumps, heavy-duty rotary fluid power generators, and a strategic B2B industrial supplier of alternative hydraulic components. The AP100, AP200, and AP300 Series High-Pressure Axial Pressure-Compensated External Hydraulic Gear Pumps—specifically focusing on critical replacement configurations like AP300/63 S 818 (Single Pump / Anti-clockwise) and AP300/63 D 280 (Single or Multiple Pump Setup / Clockwise)—are engineered and precision-manufactured as high-end, heavy-duty, and 100% drop-in interchangeable alternatives to the global market benchmark: the Casappa AP Series ruggedized gear pumps. This platform is universally specified across high-frequency vocational fleets and stationary networks due to its compact structural outline, high tolerance for destructive spike pressure loads, and superior mechanical efficiency. It serves as the main hydraulic power engine in heavy refuse compactor trucks, truck-mounted knuckle-boom cranes, underground mining drill rigs, specialized municipal multi-tool chassis, and industrial high-pressure metal shears.

Operating as the reliable pressure generator inside mobile and industrial open-circuit hydraulic systems, gear pumps face extreme challenges under continuous high pressure (up to 230 bar) and fluctuating shaft velocities. Standard alternative aluminum alloy gear pumps often suffer from volumetric efficiency drops caused by housing expansion or premature galling along the gear journal interfaces. Genlu’s premium AP300/63 series replacement assemblies precisely replicate the original factory metallurgical tolerances, bearing lubrication pathways, and dynamic axial balancing methods outlined in the original Casappa manuals. Built with a heavy-duty high-strength cast iron 3-piece construction (front cover, body, and rear cover), this unit resists structural distortion under peak shock loading. Whether your system uses standard SAE flange mounts, specified input shafts (such as SAE splined or straight keyed shafts represented by option codes 818 and 280), or split flange/threaded ports, our pumps deliver 100% mechanical and functional drop-in interchangeability. Prior to delivery, every pump undergoes 100% Full-Simulation Condition Testing to verify continuous volumetric delivery, tight internal slip tolerances, and optimized mechanical torque efficiency under maximum rated limits.

Technical Specifications 

• Product Pump Classification: AP300 Series Heavy-Duty Axial-Compensated External Hydraulic Gear Pump (100% Casappa cross-compatible)

• Specific Model Cross-Reference Configuration Breakdown:

  • AP300/63 S 818 (AP300: Frame size 300 heavy cast iron series; 63: Displacement index code; S: Left-hand rotation / single pump configuration; 818: Standard SAE splined/keyed drive shaft combined with specified split-flange hydraulic porting scheme)

  • AP300/63 D 280 (AP300: Frame size 300 series; 63: Displacement index code; D: Right-hand rotation / single pump or modular multiple pump configuration; 280: Standard cylindrical keyed shaft paired with rear/side threaded port layout)

• Comprehensive Family Displacement Boundaries:

  • AP100 Series: Micro-displacement frame footprint spanning 1.0 to 10.0 $cc/rev$

  • AP200 Series: Medium-displacement frame footprint spanning 4.0 to 30.0 $cc/rev$

  • AP300/63 Specification: Heavy-displacement frame sector, where the公称 index 63 yields a precise geometric volume of 63.7 $cc/rev$ (Alternative volumes like 43, 50, and 73 $cc/rev$ are also available)

• Maximum Continuous Rated Pressure Boundary: 230 bar (23 MPa / 3335 PSI)

• Maximum Intermittent Peak Pressure Threshold: Up to 250 bar to 270 bar under rapid fluid blockages

• Permissible Operational Velocity Spectrum: 450 RPM minimum to 2500 RPM maximum (Optimized for variable low-idle diesel power take-off (PTO) matching)

• Volumetric Efficiency Performance Index: Maintained at $\ge$ 96% under continuous 1500 RPM at full 230 bar loading

• Operating Fluid Temperature Envelope: From -25 °C up to +85 °C under standard continuous operation, backed by high-grade Nitrile/Viton sealing configurations

• Total Pump Assembly Net Dry Mass: Approximately 18.5 kg to 21.0 kg for the AP300/63 single pump setup

Key Technical Advantages:

• High-Rigidity Heavy-Duty 3-Piece Cast Iron Body Architecture: Unlike conventional aluminum gear pumps, the AP300/63 features a high-density cast iron front cover, gear casing, and rear cover. Under sustained 230 bar operation, this rigid iron housing minimizes elastic expansion, preventing gear teeth from contacting or scoring the internal chamber walls, which helps double the service life under high-pressure parameters.

• Heavy-Load Self-Lubricating DU Bushings and One-Piece Forged Gear Shafts: The gears and drive shafts are forged from high-alloy steel and precision ground, with carbon-nitride hardened surfaces. They run on heavy-duty self-lubricating DU bushings that utilize a controlled high-pressure oil film diverted from the discharge side. This hydrodynamic lubrication configuration absorbs severe radial loads caused by the high internal pressure differential, protecting the shaft journals from binding.

• Dynamic Floating Axial Thrust Pressure Compensation Boards: The internal gear group is paired with high-precision bimetallic floating thrust plates backed by asymmetrical “3”-shaped pressure-loading seals. As system pressure rises, it increases the sealing force against the gear faces, automatically adjusting for micrometer-scale axial clearances caused by thermal expansion. This compensation mechanism holds internal bypass leakage below 4% to maintain high volumetric output even at low operating speeds.

• Modular Multi-Pump Tandem Stacking Capability: The AP300 series features a highly flexible modular configuration. Using standard tandem coupling kits, an AP300 can be coupled with an AP200 or AP100 pump to form double or triple pump configurations (such as the D 280 multiple series). This configuration allows a single engine or motor PTO drive shaft to power multiple independent hydraulic circuits, lowering overall component costs and saving engine bay space.

Application Areas:

• Municipal Vocational Equipment & Heavy Refuse Compactor Fleets: High-pressure packer blade actuation circuits, heavy container lifting mechanisms, and ejector panel cylinders.

• Truck-Mounted Knuckle-Boom Cranes & Heavy Hydraulic Winch Systems: Outrigger deployment valves, primary winch motor supply loops, and main telescopic boom extension systems.

• Underground Mobile Drill Rigs & Specialized Construction Machinery: Rotation and feed circuits for mining drill rigs, auxiliary hydraulic steering modules, and heavy track tensioning networks.

Expert Maintenance Tips:

• Strict Dry-Run Prohibitions and Mandatory Initial Casing Priming: The internal DU bushings and floating thrust plates in the AP300 series require fluid lubrication at the first turn of the shaft. Never jog or start the drive motor with a dry pump housing after a new installation or system teardown. Fill the pump chamber with clean hydraulic oil via the suction port and rotate the input shaft by hand to coat the gear teeth and bushing surfaces, preventing immediate friction damage at startup.

• Inlet Vacuum Limits and Anti-Cavitation Sizing Rules: The 63.7 $cc/rev$ displacement of the AP300/63 pump creates a strong fluid draw that is highly sensitive to suction restrictions, especially in cold environments. Inlet line fluid velocity should be held between 0.5 and 1.2 m/s, using a coarse 100-mesh suction strainer rather than a dense filter, and the pump should be positioned below the minimum oil level of the reservoir. Restricted inlet lines or air leaks can cause severe cavitation, producing a harsh metallic rattling sound and pitting the internal gear faces.

• Sustained Fluid Temperature Control and Cleanliness Standards: The fine clearances between the gear faces and thrust plates are highly sensitive to solid particulate contamination. The hydraulic circuit must use 10-to-20 micron high-pressure return filtration to maintain oil cleanliness at or above NAS Grade 8 (ISO 4406 19/16/13), while keeping operating temperatures below 60 °C via heat exchangers. Operating above 85 °C thins the oil film, reducing volumetric efficiency and accelerating shaft seal degradation.