GPA1-2-2-EK1-20R6.3 Vickers Internal Gear Pump 10MPa

Product Overview

Technical Specifications 

• GPA: Internal Gear Pump
• 1: Series number (Size Group 1)
• 2: Pressure rating (10 MPa / 100 bar)
• 2: Nominal displacement (2 ml/r)
• EK1: Shaft type (Φ12 mm cylindrical with keyway)
• 20: Design sequence number
• R: Rotation (Clockwise CW)
• 6.3: Integral relief valve setting (6.3 MPa)

• Technology Origin: American Vickers Corporation (now Eaton)
• Pump Type: Fixed Displacement Internal Gear Pump
• Displacement Range: 1.76 ~ 63.6 ml/r (cc/rev)
• Size Groups: GPA1 (1/2/4/6/8 ml/r), GPA2 (10/12.5/16/20/25 ml/r), GPA3 (25/31.5/40/50/63 ml/r)
• Rated Pressure: 6.3 MPa (63 bar) / 10 MPa (100 bar), model-dependent
• Maximum Speed: 2,000 ~ 3,000 r/min (size-dependent)
• Rotation: R = Clockwise (standard) / L = Counterclockwise
• Shaft Options: GPA1 = Φ12 mm / GPA2 = Φ20 or Φ25 mm / GPA3 = Φ25 or Φ30 mm
• Mounting: ISO metric 4-bolt flange
• Port Threads: GPA1 = G1/2″ / GPA2 = G1″ / GPA3 = G1-1/4″ (BSPF)
• Configuration: Single / Duplex / Triplex / Quadruplex
• Options: Internal pressure relief valve, heavy-duty bearings for indirect drives

• At 0.7 MPa: Flow 4.2 L/min, Power 0.1 kW
• At 2.5 MPa: Flow 4.1 L/min, Power 0.25 kW
• At 5.0 MPa: Flow 4.0 L/min, Power 0.50 kW
• At 7.0 MPa: Flow 3.9 L/min, Power 0.70 kW
• At 10.0 MPa: Flow 3.7 L/min, Power 0.90 kW

• At 0.7 MPa: Flow 6.8 L/min, Power 0.15 kW
• At 2.5 MPa: Flow 6.6 L/min, Power 0.40 kW
• At 5.0 MPa: Flow 6.5 L/min, Power 0.70 kW
• At 7.0 MPa: Flow 6.3 L/min, Power 0.90 kW
• At 10.0 MPa: Flow 6.0 L/min, Power 1.30 kW

• GPA2-6 @ 0.7 MPa: Flow 10.3 L/min, Power 0.60 kW
• GPA2-6 @ 10 MPa: Flow 9.5 L/min, Power 2.00 kW
• GPA2-10 @ 0.7 MPa: Flow 16.6 L/min, Power 0.90 kW
• GPA2-10 @ 10 MPa: Flow 15.6 L/min, Power 3.20 kW
• GPA2-16 @ 0.7 MPa: Flow 26.2 L/min, Power 1.50 kW
• GPA2-16 @ 10 MPa: Flow 25.0 L/min, Power 5.10 kW

• GPA3-25 @ 0.7 MPa: Flow 38.0 L/min, Power 2.20 kW
• GPA3-25 @ 10 MPa: Flow 33.0 L/min, Power 7.10 kW
• GPA3-40 @ 0.7 MPa: Flow 61.0 L/min, Power 3.00 kW
• GPA3-40 @ 10 MPa: Flow 56.0 L/min, Power 10.8 kW
• GPA3-63 @ 0.7 MPa: Flow 96.0 L/min, Power 4.40 kW
• GPA3-63 @ 10 MPa: Flow 90.0 L/min, Power 16.8 kW

• GPA1 Group: Flange A=82, B=80, Housing D=Φ63, Shaft d=Φ12, Mounting holes N=4
• GPA2 Group: Flange A=120, B=115, Housing D=Φ100, Shaft d=Φ20 (Φ25), Mounting holes N=6 (8)
• GPA3 Group: Flange A=152, B=150, Housing D=Φ125, Shaft d=Φ25 (Φ30), Mounting holes N=8 (10)

• Recommended Hydraulic Oil: 20~45 cSt (ISO VG 32/46)
• Filtration Precision: ≤25 μm
• Working Temperature Range: 0°C ~ 68°C

Key Technical Advantages

• Involute Internal Gear Meshing Design: The GPA series employs precision-machined involute-profile internal/external gear sets where the internal gear (driven) and external gear (driver) create multiple simultaneous meshing seal chambers. Compared to external gear pumps, the internal meshing architecture achieves significantly higher contact ratio, resulting in smoother volumetric displacement per revolution. This fundamentally reduces flow and pressure pulsation, making the GPA series ideal for precision machine tool servo systems requiring exceptional pressure stability.
• Axial Floating Side Plate Compensation: The pump’s end covers integrate elastomeric-loaded floating side plates that automatically press against the gear faces using discharge pressure, providing real-time axial clearance compensation. This self-adjusting mechanism eliminates efficiency degradation caused by gear face wear over time, ensuring stable volumetric output throughout the pump’s service life. The axial compensation system maintains volumetric efficiency of 88%–92% even at the full 10 MPa rated pressure.
• Ultra-Low Noise & Pulsation Operation: Thanks to the involute internal gear meshing geometry and optimized tooth count ratios, the GPA series achieves pressure pulsation levels substantially lower than equivalent external gear pumps. Sound pressure levels are significantly below comparable external gear pump specifications, creating a more comfortable operating environment while reducing hydraulic line vibration and fatigue-related failures. This characteristic provides a decisive advantage in noise-sensitive environments such as injection molding facilities and food processing plants.
• Aluminum Alloy Housing with Load Balancing System: The pump body is die-cast from high-strength aluminum alloy, reducing weight by over 40% compared to cast iron equivalents for easier installation and maintenance. The GPA series’ proprietary load balancing system on guide bushings distributes radial bearing loads evenly, dramatically reducing bearing wear rates and extending service life. Combined with the heavy-duty bearing option, the pump can withstand belt-drive and other indirect drive configurations.
• Multi-Pump Modular Configuration: The GPA series supports rapid assembly of single pumps into duplex, triplex, or quadruplex configurations via standardized connection kits, with each section independently displacing different volumes on a common drive shaft. This modular design flexibly addresses multi-circuit hydraulic system requirements — such as injection molding machines that simultaneously need high flow for rapid mold closing and low flow for precision holding pressure.

Application Areas

• Precision Machine Tool Hydraulics: Hydraulic power sources for spindle clamping, tool changer actuation, and table feed on grinding machines, lathes, milling machines, and machining centers
• Injection Molding Equipment: Hydraulic drives for mold clamping units, injection carriage movement, and ejector mechanisms
• Die-Casting Machines: Clamping and shot-end hydraulic systems for cold-chamber and hot-chamber die-casting machines
• Rubber Vulcanizing Presses: Hydraulic power for mold closing and part ejection in rubber vulcanizing operations
• Tube Bending & Shearing Machines: High-pressure hydraulic drives for pipe bending forming and metal sheet shearing
• Packaging Machinery: Hydraulic actuators for food packaging machines and paper product processing equipment
• Engineered Wood Panel Processing: Hydraulic systems for particleboard and MDF hot-pressing equipment
• Test & Simulation Equipment: Hydraulic loading sources for material testing machines and fatigue test rigs
• Battery Forklifts & Lifting Equipment: Lift hydraulic systems and power steering assist systems

Expert Maintenance Tips

• Mandatory Pre-Start Priming: Before initial startup or after extended downtime, the GPA pump must be filled with clean hydraulic oil through the inlet port to ensure formation of a protective oil film on gear faces and guide bushing surfaces. Dry starting will cause irreversible damage to gear end faces and side plates within seconds. For initial startup, run the pump at minimum speed under no-load conditions for 5–10 minutes to gradually purge air from the pump cavity and suction line.
• Strict Fluid Cleanliness Control: The GPA series requires system filtration to ≤25 μm. Install an appropriately rated high-pressure filter on the pump discharge line and a magnetic plug detector on the return line. Sample oil regularly for particle count analysis — replace filter elements immediately if contamination exceeds specifications. The internal gear meshing clearance is relatively small; contaminant particles entering the pump will cause scoring, leading to increased internal leakage, slower pressure build-up, and elevated oil temperature.
• Suction Line Integrity Verification: Internal gear pumps demand exceptionally tight suction line sealing. Loose fittings, aged/deformed suction hoses, or clogged strainers will cause flow starvation, producing sharp noise and cavitation damage. Inspect all suction line connection torque regularly; check suction hose inner wall condition every 2,000 operating hours and replace immediately if aging or deformation is detected. Inlet flow velocity should be maintained below 1.2 m/s with suction negative pressure no lower than -0.02 MPa.
• Shaft Alignment & Coupling Selection: Shaft alignment between pump and drive motor should be within ≤0.05 mm radial offset and ≤1° angular misalignment. Use flexible couplings to accommodate minor thermal expansion shifts. The pump shaft must not additional radial or axial loads from the coupling. An overly tight coupling will impose unintended loads on bearings and shaft seals, leading to vibration, oil leakage, or abnormal wear after a period of operation.
• Relief Valve Setting & Motor Power Verification: GPA series pumps can be equipped with integral pressure relief valves (e.g., GPA1-2-2-EK1-20R6.3 comes standard with a 6.3 MPa relief valve). The relief setting should be slightly above the system’s maximum working pressure but must not exceed the pump’s rated pressure. When replacing a pump with a different displacement or pressure rating, always recalculate the required drive motor power to prevent motor overload and tripping during pressure ramp-up.