Servo valves are a close relative of the proportional valve and are based on an electrical torque motor which produces a small deflection proportional to…
Author: Jack
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…
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.…
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.…
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…
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…
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…
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…
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…
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…