Piston machines
Hydrostatic displacement machines , displacement chamber machines , pump with banked pistons/in-line piston pump
Pressure pulsation-induced oscillations
to the pressure alteration in the pump from the suction phase to the pressure phase. Their fundamental frequency depends on the number of displacement units in the pump, while their amplitude is defined [...] pressure rise . They generate structure-borne noise in the pump housing that is an important element in the overall noise emissions from a pump.
Intake height
and intake port on the pump. If it is exceeded, the pump will not be completely filled, i.e. air bubble cavitation will occur. The intake height is dependent on the type of pump and the viscosity of the
Closed circuit
circulates from the pump to the actuator and from there straight back into the suction line of the pump. The main difference between this and an " open circuit " is that the hydraulic pump in a closed circuit [...] actuator (hydraulic motor). This effectively "clamps" the pump from both the suction side and pressure side. The leakage that occurs at the pump and the individual components in the form of escaping leakage [...] low-pressure charge pump. As in such systems a very small volume of oil is circulated (e.g. approx. 8 l at 300 kW) the oil must be continuously renewed and cooled. For this purpose, the charge pump also operates
Intake characteristic
cavitation occurs, either the hydraulic fluid must be fed to the pump (pump under the tank) or it must be supplied with pressure (charge pump) [...] capability of displacement pumps to draw the required flow rate from a tank. Apart from the type of pump, the intake characteristic is determined by the magnitude of the vacuum produced during the suction [...] suction phase. In addition, the intake characteristic also depends on the rotation speed of the pump, the intake cross-section and the viscosity of the hydraulic fluid. The higher the rotation speed and the
Suction filtering
by the hydraulic pump . Theoretically ideal, as then the pump is also used optimally. In reality, however, as the dirt absorbing capacity drops, there is a risk of cavitation in the pump. Therefore, suction
Accumulator charging valve
task of switching the constant pump, which charges a hydraulic accumulator , to pressure-free circulation as soon as it reaches its charging pressure and to switch the pump back on when the accumulator pressure [...] system should ensure the pump can be switched on and off exactly under the preselected pressures, have a small pressure switching difference (e.g. 5 to 10 bar), permits the pump to be switched on and off
Hydrostatic transmission
on). If pump and motor are close together within a confined space, the term used is integral hydrostatic transmission . A hydrostatic transmission may be based on the combination variable pump fixed d [...] displacement motor , ( primary control ), constant pump variable motor ( secondary control ) or variable pump — variable motor ( primary and secondary control ).
Flow rate
flow rate Q of a pump is calculated from the volume per revolution Vg, the rotary speed of the pump n and the volumetric efficiency factor ηv of the pump. Calculate the flow rate of a pump directly and easily
Switching methods for hydraulic pumps
traverse circuits ). Series circuit : Pump 1 leads to pump 2. This circuit is used to improve the filling of a high-pressure pump or to reach a higher output pressure at pump 2 (e.g. in the case of some internal [...] A distinction is then made between ( Figure S 17 ): two-circuit or multi-circuit switches : Each pump supplies its own circuit. Parallel circuit : Several pumps work together for a single consumer. This