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Parker PGP640 Series Fixed Displacement External Gear Pump

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On 2026-10-24
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Product Description

The PGP640 is the largest frame size of Parker PGP600 heavy-duty cast iron gear pump family, designed for demanding mobile and industrial hydraulic applications. Its matching gear motor is PGM640. It adopts robust interlocking two-piece cast iron housing with excellent rigidity and low-noise performance. Available in single, tandem, multi-section and common-inlet cross-frame configurations. This pump delivers large flow output and reliable high-pressure performance for heavy machinery requiring long service life and stable continuous operation.

1. Overview

PGP640 is an external-meshing fixed displacement gear pump equipped with pressure-balanced thrust plates and precision ground gear pairs. The interlocking housing structure minimizes deflection under high pressure and reduces operating noise. Its modular design supports flexible selection of mounting flanges, shaft ends, port layouts, seal materials and integrated valves. Clockwise (CW) and counter-clockwise (CCW) rotation are standard options. It is the preferred high-flow heavy-duty cast iron gear pump for large tractors, construction equipment, forestry machines and municipal vehicles.

2. Construction & Key Features

  1. Interlocking high-strength cast iron housing: Outstanding mechanical rigidity, minimal pressure deformation, strong resistance to shock, dust and wide temperature fluctuations, low noise level.
  2. Pressure-balanced thrust plates: Automatically compensates axial clearance, maintains high volumetric efficiency throughout service life and reduces friction and wear.
  3. Heavy-duty journal bushing design: Fluid-lubricated bearings provide stable load capacity for continuous operation. Axial thrust on the drive shaft is not permitted. Outboard bearing versions are optional for applications with heavy radial shaft loads.
  4. Precision ground optimized gear set: Low flow ripple, quiet operation, volumetric efficiency up to 97%.
  5. Modular construction: Multiple SAE flanges, rectangular through-bolt flanges, shaft ends and port styles are optional. Tandem / multi-section pumps with common inlet can supply independent hydraulic circuits from a single 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-port relief valve, etc.

3. Main Technical Specifications

  • Displacement range: 30 ~ 80 cm³/rev (codes: 0300, 0350, 0450, 0550, 0650, 0750, 0800)
  • Max continuous pressure:
    • 30–65 cm³/rev: 275 bar (3989 psi)
    • 75 cm³/rev: 235 bar (3408 psi)
    • 80 cm³/rev: 215 bar (3118 psi)
  • Max intermittent pressure: up to 310 bar (4500 psi)
  • Speed range: 500 ~ 3000 rpm
  • Rotation: CW / CCW
  • Standard mounting: SAE flanges, rectangular through-bolt flange; custom flanges available on request
  • Shaft options: keyed shaft, SAE splined shaft, tapered shaft
  • Port options: SAE split flange, SAE straight thread, BSPP, metric thread; side or rear port layout
  • 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 requirement: Minimum absolute inlet pressure ≥0.8 bar to avoid cavitation
  • Approx. weight: 19.1 ~ 24.0 kg (single pump, varies by displacement and configuration)

4. Typical Applications

  • Construction machinery: large excavators, backhoe loaders, heavy skid steer loaders, large aerial work platforms
  • Agricultural equipment: large tractors, combine harvesters, forage harvesters
  • Material handling: heavy-duty forklifts, large loading attachments
  • Forestry machinery, sanitation trucks, municipal vehicles and heavy stationary hydraulic power units

5. Ordering Code Explanation

Example model: PGP640B0550HP4D1NE4E4

  • PGP640: Series identifier (PGM640 = matching gear motor)
  • A: Single pump; B: Tandem / multi-section pump
  • 0550: Displacement code (55 cm³/rev)
  • C / E: Rotation (CCW / CW)
  • P4: Flange code
  • D1: Shaft type code
  • N: Seal material code
  • E4E4: Port configuration
  • Suffix codes: integrated valve, revision version

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

6. Operation Guidelines

  1. Direct drive by flexible coupling is recommended. Avoid excessive radial shaft loads; select outboard bearing version if significant radial force exists.
  2. Suction line must be sized adequately. Keep low inlet pressure drop to prevent cavitation damage to thrust plates and gear sets.
  3. Recommended filtration: 10 μm hydraulic filter. Regular oil change is required. Although tolerant to contamination, solid particles accelerate thrust plate wear.
  4. Built-in relief valve is only for system protection. It is NOT designed for continuous throttling or pressure regulation duty.
  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

  • PGP640: Largest cast iron frame in PGP600 family, displacement 30–80 cc/rev, high flow heavy-duty
  • PGP610: Small frame of PGP600 series
  • PGP625: Compact cast iron frame, displacement 8–32 cc/rev
  • PGP620: Medium cast iron frame, displacement 16–52 cc/rev
  • PGP502 / 503 / 505 / 511 / 517: Lightweight aluminium pumps of PGP500 series
  • PGP350 / PGP365: Traditional three-piece cast iron pumps
  • PGM640: Gear motor sharing identical housing, cannot be used as a pump.

 

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