Parker PGP502 Series Fixed Displacement External Gear Pump

Product Description

The PGP502 belongs to Parker PGP500 aluminium gear pump family, a compact, lightweight high-performance fixed-displacement external gear pump for mobile hydraulics. Its matching gear motor model is PGM502. Different from cast iron PGP350 / PGP365, the PGP502 adopts high-strength aluminium housing for light weight, high power density and low noise, widely used in compact construction machinery, agricultural machines, material handling and small hydraulic power packs. It supports single pump and tandem multi-section pump configurations.

1. Overview

PGP502 is an external meshing fixed displacement gear pump with pressure-balanced thrust plates and journal bearing design. The 9-tooth gear profile reduces flow pulsation and noise. Modular design provides flexible selections of flanges, shafts, port forms, seals and integrated valves. Standard rotation options are clockwise (CW) and counter-clockwise (CCW). It is a preferred solution for space-limited and weight-sensitive mobile hydraulic systems.

2. Construction & Key Features

1. High-strength aluminium housing: Light weight, good heat dissipation, high rigidity, suitable for compact mobile equipment.
2. Pressure-balanced thrust plates: Automatically compensates axial clearance, maintains high volumetric efficiency over service life, reduces friction and wear.
3. Journal bearing design: Lubricated by hydraulic fluid, good load capacity for continuous operation. Axial thrust on the shaft is not permitted. External bearing versions are available for high radial load conditions.
4. Precision ground 9-tooth gear set: Optimised tooth profile, low flow pulsation, quiet operation, volumetric efficiency up to 96%.
5. Modular construction: Wide selections of mounting flanges, shaft ends, inlet/outlet ports and seal materials. Tandem multi-pump assembly is supported to supply separate hydraulic circuits from one drive source.
6. Integrated valve options:
   • Relief valve with anti-cavitation check valve
   • Priority flow valve
   • Load-sensing unloading valve
   • Solenoid unloading relief valve, cross relief valve, etc.

3. Main Technical Specifications

• Displacement range: 0.8 ~ 7.9 cm³/rev
• Max continuous pressure: up to 280 bar (4060 psi); pressure rating decreases for larger displacement versions
• Max allowable speed: 3600 rpm
• Rotation: CW / CCW
• Standard mounting: SAE A, rectangular, through-bolt flanges; custom flanges on request
• Shaft options: keyed shaft, SAE splined shaft
• Port options: SAE split flange ports, BSPP thread, metric threaded ports; side/rear port configurations
• Compatible fluid: Anti-wear mineral hydraulic oil. FPM fluorocarbon seals optional for water-glycol, emulsion and fire-resistant fluids; FPM seals mandatory for phosphate ester fluids.
• Recommended viscosity: 16 ~ 100 cSt
• Suction condition: Minimum absolute inlet pressure ≥0.8 bar to avoid cavitation
• Weight: approx. 2.2 ~ 4.0 kg (varies by displacement and configuration)

4. Typical Applications

• Compact construction equipment: mini excavators, small skid steer loaders, aerial work platforms
• Agricultural machinery: planters, small harvesters, tractor auxiliary hydraulics
• Material handling: pallet trucks, small tailgates, compact lifting units
• Mobile hydraulic power packs, forestry equipment and small sanitation vehicles

5. Ordering Code Explanation

Example model: PGP502A0012CH1H1NE3E2B1B1

• PGP502: Series code (PGM502 = matching gear motor)
• A: Single pump; B: Tandem / multi-section pump
• 0012: Displacement code
• C / E: Rotation (CCW / CW)
• H1: Flange code
• H1: Shaft type
• N: Seal material
• E3E2: Port configuration
• Suffix codes: integrated valve, revision version

Note: Verify port layout, shaft diameter, rotation and built-in valves before replacement.

6. Operation Guidelines

1. Direct drive with flexible coupling is recommended. Avoid excessive radial shaft loads; select external bearing version if radial load exists.
2. Suction line size must be sufficient. Keep low pressure drop at inlet to prevent cavitation damage to thrust plates and gears.
3. Recommended filtration: 10 μm hydraulic filter. Regular oil change is required. Though tolerant to contamination, solid particles accelerate thrust plate wear.
4. Built-in relief valve is only for system protection, not designed for continuous throttling or pressure regulation.
5. For tandem pumps, each section has its independent pressure rating. Check displacement and pressure separately for every section during selection.

7. Differentiation from Related Series

• PGP502: Aluminium housing, small displacement, compact, low noise
• PGP505 / PGP511 / PGP517: Larger displacement models in PGP500 aluminium series
• PGP350 / PGP365: Cast iron heavy-duty pumps, higher flow and rugged duty
• PGM502: Gear motor with identical housing, cannot be used as a pump