Displacement chamber machines
machines whereby the displacement units are generally pistons moved in a linear manner such as a pump with banked pistons/in-line piston pump , displacement chamber pump, axial piston machine , radial piston
Servo-suction valve
open circuit. Since what had been the pressure line then becomes the suction line, the servo-suction valve is intended to prevent a vacuum forming in this line by suction oil from the container. Servo-suction
Non-linearity
relationship between two variables is not sufficiently linear, i.e. it does not satisfy the superposition and amplification principle. The term covers non-linear characteristic curves, multiplication points for
Analogue
relationship to the first variable. The relationship between these two variables can be linear, but does not have to be linear. Basic feature: An analogue signal can take any magnitude within the range between
Controller
this. These are divided into three main groups: Linear controllers have a linear connection between the control deviation and correcting variable. Non-linear controllers do not have dynamic performance, i [...] i.e. they work without delay and are characterised by a non-linear characteristic curve. Sampling controllers sample a constant variable, form the corrective signal and keep it constant until the next
Piston machines
Hydrostatic displacement machines , displacement chamber machines , pump with banked pistons/in-line piston pump
Surface foam
keeping the return and suction line as far apart as possible, using barriers and angled walls (covers) to prevent any direct flow from the return line to the suction line. More foam tends to form if the
Describing function
Describing function is the term used on non-linear transfer elements for the frequency response while only taking into account the fundamental oscillation of the , recorded or calculated for various constant [...] amplitudes of the sinusoidal input signal . During the determination of the frequency response of non-linear transfer elements, the curve shape and amplitude of the fundamental oscillation of the mostly anharmonic [...] on Fourier analysis or a suitable measuring method represents a certain linearisation of the non-linear element (see DIN 19 226) (VDI-VDE 2600).
Laminar flow resistor
Flow resistor () with laminar flow, e.g. capillary gap. Has a largely linear flow rate pressure characteristic .
Decompression shock
If a chamber at pressure p is suddenly connected to a drain line (e.g. on switching over a directional valve ) then the compression energy stored in the fluid is suddenly released, as a result the compression [...] compression volume at the start meets at high speed the column of fluid in the drain line and causes there a measurable and audible pressure increase ( energy content of a hydraulic fluid).