Parker PAVC33 - Variable Displacement Piston Pump

All control is achieved by the proper positioning of the swash plate. This is achieved by a servo piston acting on one end of the swash plate working against the combined effect of the off-setting forces of the pistons and centering spring on the other end. The control spool acts as a metering valve which varies the pressure behind the servo piston. The amount of flow produced by the Parker Piston Pump is dependent upon the length of stroke of the pumping pistons. This length of stroke, in turn, is determined by the position of the swash plate.

Maximum flow is achieved at an angle of 17°. The rotating piston barrel, driven by the prime mover, moves the pistons in a circular path and the piston slippers are supported hydrostatically against the face of the swash plate. When the swash plate is in a vertical position, perpendicular to the centerline of the piston barrel, there is no piston stroke and consequently no fluid displacement. When the swash plate is positioned at an angle, the pistons are forced in and out of the barrel and fluid displacement takes place. The greater the angle of the swash plate, the greater the piston stroke.

The centerline of the pumping piston assembly is offset from the centerline of the swash plate. Therefore, as shown on the accompanying Figure 1A, the pistons’ effective summation force tends to destroke the swash plate to a vertical (neutral) position. This destroking force is balanced as the swash plate is angled by the force of the servo piston.

Features

• High Strength Cast-Iron Housing
• Built-In Supercharger
• High Speed Capability - 3000 RPM
• Two Piece Housing for Ease of Service
• Cartridge Type Controls - Field Changeable
• Replaceable Bronze Clad Port Plate
• Airbleed Standard for Quick Priming
• Hydrodynamic Cylinder Barrel Bearing
• Full Pressure Rating on Water Glycol Fluids
• Filtered and/or Cooled Drain Line Capable - 7 bar (100 PSI) Maximum

Controls

• Pressure Compensation
• Remote Pressure Compensation
• Load Sensing
• Power (Torque) Limiting
• Power Limiting and Load Sensing
• Adjustable Maximum Volume Stop
• Electrohydraulic Pressure
• Electrohydraulic Flow and Pressure (Servo Control)
• Low Pressure Standby