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Parker PGP625 Series Fixed Displacement External Gear Pump

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On 2026-10-24
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Product Description

The PGP625 belongs to Parker PGP600 heavy-duty cast iron gear pump family. It is a robust, low-noise fixed-displacement external gear pump developed for demanding mobile and industrial hydraulic applications. Its matching gear motor is PGM625. Built with interlocking two-piece cast iron construction, the PGP625 delivers excellent rigidity and stable high-pressure performance. It supports single, tandem, multi-section and common-inlet cross-frame configurations. Widely used in heavy mobile machinery that requires long service life, high efficiency and reliable continuous operation.

1. Overview

PGP625 is an external-meshing fixed displacement gear pump equipped with pressure-balanced thrust plates and precision ground gear pairs. The interlocking structure effectively reduces noise and housing deformation under high pressure. Its modular platform provides flexible selections of mounting flanges, shaft ends, port layouts, seal materials and integrated valves. Clockwise (CW) and counter-clockwise (CCW) rotation versions are standard. It is a preferred heavy-duty cast iron gear pump for agricultural tractors, backhoe loaders, skid steer loaders, forestry and municipal equipment.

2. Construction & Key Features

  1. Interlocking high-strength cast iron housing: Superior mechanical rigidity, minimal pressure-induced deformation, outstanding resistance to shock, dust and wide temperature fluctuations, low noise emission.
  2. Pressure-balanced thrust plates: Automatically compensates axial clearance, preserves high volumetric efficiency over the whole service cycle and reduces friction and wear.
  3. Heavy-duty journal bushing design: Fluid-lubricated bearings support stable continuous running. 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 design: Multiple SAE flanges, rectangular through-bolt flanges, shaft ends and port styles are available. 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: 8 ~ 32 cm³/rev (codes: 0080, 0100, 0160, 0200, 0250, 0290, 0320)
  • Max continuous pressure: up to 275 bar (3988 psi); pressure rating decreases for larger displacement models
  • Max intermittent pressure: up to 300 bar (4351 psi)
  • Speed range: 500 ~ 3000 rpm; maximum speed reduces for larger displacement codes
  • 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: 10.5 ~ 12.8 kg (single pump, varies by displacement and configuration)

4. Typical Applications

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

5. Ordering Code Explanation

Example model: PGP625B0250HP3D1NE3E3

  • PGP625: Series identifier (PGM625 = matching gear motor)
  • A: Single pump; B: Tandem / multi-section pump
  • 0250: Displacement code (25 cm³/rev)
  • C / E: Rotation (CCW / CW)
  • P3: Flange code
  • D1: Shaft type code
  • N: Seal material code
  • E3E3: 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

  • PGP625: Cast iron interlocking design, displacement 8–32 cc/rev, compact heavy-duty frame within PGP600 family
  • PGP610: Smaller cast iron frame of PGP600 series
  • PGP620: Medium cast iron frame, displacement 16–52 cc/rev
  • PGP640: Largest cast iron frame in PGP600 family, higher displacement
  • PGP502 / 503 / 505 / 511 / 517: Lightweight aluminium pumps of PGP500 series
  • PGP350 / PGP365: Traditional three-piece cast iron pumps
  • PGM625: Gear motor sharing identical housing, cannot be used as a pump

 

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Older Parker PGP620 Series Fixed Displacement External Gear Pump