Displacement | Gear | Pumps

Performance Data
Series D Fixed Displacement, Pressure-Loaded Gear Pump
Features
• Pressure-loaded design
• Efficient, simple design - few moving parts
• Exceptionally compact and lightweight for
their capacity
• Efficient at high pressure operation
• Resistant to cavitation effects
• High tolerance to system contamination
• Reliable under cold weather operation
• Sleeve-bearing construction
• Multi-fluid compatibility
Controls
• Optional built-in relief valve
• Consult factory for special controls
Specifications
Flow Ratings:
.5 GPM (1.9 LPM) to 2.7 GPM (10.2 LPM)
(At 1000 RPM) See next page for additional
flow data.
Pressure Ratings:
D05 thru D22 - 2500 PSI (172 Bar) continuous
D27 - 2000 PSI (138 Bar) continuous
Speed Ratings:
D05 thru D22 - 500 to 4000 RPM
D27 - 3000 RPM
Mounting:
SAE-AA - 2-Bolt Flange
4-Bolt Flange
Housing Material:
Die-Cast Aluminum

Installation Data
Inlet Conditions:
10 in. hg. max. vacuum condition
(At 1800 RPM)
5 in. hg. max. vacuum condition
(At max. RPM)
20 PSI (1.4 Bar) max. positive pressure
Operating Temperature Range:
-40°F to 185°F
(-40°C to 85°C)
Filtration:
Maintain SAE Class 4

A Parker pressure-loaded gear pump consists of two, intermeshing, hardened-steel, precision-ground gear assemblies. These precision gears are enclosed by a high-strength, die-cast aluminum front cover, back cover and a high-yield, strength-extruded aluminum
center section.

Gear assemblies consist of one drive gear, shrinkfitted on a precision-ground and polished drive
shaft. This shaft extends outside the pump to permit coupling to an external prime mover. The second
gear, being the driven gear, is also shrink-fitted on a precision-ground and polished driven shaft. Retaining rings, which are installed in grooves provided on the shaft, ensure that the gears will not move axially, and a key keeps the drive gear from moving radially. A lip-type, shaft seal is provided at the drive shaft to prevent external leakage of pump fluid. The sealing lip in contact with the fluid is spring-loaded. Vent passages within the housings and driven shaft communicate pump inlet pressure to the rotary seal area, thus imposing the lowest possible pressure at the rotary seal for extended seal life.

The phenolic heat shield, backup gasket, and molded rubber seal form chambers behind the steel-backed bronze wearplate. These chambers are connected either to inlet or discharge pressure. Discharge pressure, acting within the chambers, axially loads and deflects the wear plate toward the gear faces to take up gear side clearances. This pressure-loading on the wear plate increases pump efficiency by reducing internal leakage to a minimum, providing longer pump life. Pump rotation is dependent upon the proper orientation of the heat shield, backup gasket, and rubber seal in the front cover housing, the center section and rear cover, respectively. Pumping action is achieved by connecting the pump drive shaft to a prime mover, and rotating the gears away from the inlet port. Rotation causes the gear mesh to increase on the inlet side and decrease on the outlet (pressure) side.