Monthly Archives for December 2009

Hydraulic Gerotor Pump Efficiency

Overall efficiency accounts for the loss of mechanical energy due to friction, and the loss of hydraulic energy due to the leakage flow. The clearances between moving parts can be thought of as an orifice. Fluid on one side of … Continue reading

26. December 2009 by Jack
Categories: Hydraulic Pressure Control | Tags: , , | Leave a comment

Hydraulic Gerotor Pump Performance

The Hydreco Model 1919 gerotor pump has a displacement of 4.53 in3/rev. The manufacturer gives performance data up to a maximum speed of 3000 rpm. The maximum pressure curve is 2500 psi. When driven at 1200 rpm, the volumetric efficiency … Continue reading

26. December 2009 by Jack
Categories: Creation and Control of Fluid Flow | Tags: , , | Leave a comment

Load Sensing Efficiency Improvement

Load sensing was developed to improve the efficiency of a circuit. It requires a variable displacement pump; thus, it is appropriate to discuss it here. An example will illustrate the advantage provided by load sensing. An application requires a maximum … Continue reading

26. December 2009 by Jack
Categories: Creation and Control of Fluid Flow | Tags: , | Leave a comment

Hydraulic Radial Piston Pump

The principle of operation of the radial piston pump is shown in Fig. 4.16. In this case, the cylinders are positioned radially around the axis of rotation. As the shaft rotates, the connecting rods push the pistons back and forth … Continue reading

26. December 2009 by Jack
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Hydraulic Axial Piston Pump

The axial piston pump has a series of cylinders (typically 7 or 9) mounted parallel to the axis of rotation. (The arrangement is similar to shell chambers in a revolver.) Pistons are installed in the cylinders. Each piston has a … Continue reading

26. December 2009 by Jack
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Hydraulic Vane Pump Basic Operation

A vane pump (Fig. 4.7) has a series of vanes that slide back and forth in slots. There are springs in these slots that push the vanes out until the tip contacts the cam ring. (Some designs port pressurized fluid … Continue reading

25. December 2009 by Jack
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Variable Displacement Pump Hydraulic Circuits

Variable displacement pump circuits are called demand flow circuits. A simple example is shown in Fig. 4.6. (The astute reader will quickly observe that this circuit is the first circuit we have studied with no relief valve. Although no relief … Continue reading

25. December 2009 by Jack
Categories: Creation and Control of Fluid Flow | Tags: , | Leave a comment

Fixed Displacement Pump Hydraulic Circuits

A simple circuit with fixed displacement pump is shown in Fig. 4.3. Circuits with fixed displacement pumps are called constant-flow circuits. The key concept is stated below. Each revolution of a fixed displacement pump delivers a certain volume of fluid … Continue reading

25. December 2009 by Jack
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Hydraulic Fixed Displacement Pump Basic Principle

Vane and piston pumps are available as fixed or variable displacement pumps. If the cam ring is fixed in position (vane pump), or the swashplate is fixed in position (piston pump), the displacement is fixed. Gear pumps, however, are available … Continue reading

25. December 2009 by Jack
Categories: Creation and Control of Fluid Flow | Tags: , , , | Leave a comment