Constant force characteristic
motor in series connection, power-controlled pump, compressed air cylinder (connection behaviour of fluid drives). Opposite: position dependent locking , where it is possible to have an output variable which
Overload protection
Overload protection helps secure the system against excessive operating pressures. In fluid technology, the overload protection is provided by the working method of the pressure-limiting valve, which starts
Volume reduction on pressure increase
reciprocal of the Kompressionsmodul K. The value of K can be assumed to be 1400 MPa for a hydraulic fluid.
Ageing of hydraulic fluids
Damage to the hydraulic fluid primarily due to oxidisation (formation of acid residues) and polymerisation (enlargement of the hydrocarbon chains); creates sludge or resin-like coatings on device parts
Capillary tube
Newtonian fluids, the flow rate through these kinds of flow resistors is mainly determined by the viscous fluid friction, geometry and pressure difference and may be calculated fairly accurately using Hagen-Po
Laminar flow
(depending on the shape of the cross section), a laminar flow will apply. The individual elements of the fluid only move in the direction of the flow. As a result of viscosity, the local velocity across the cross
Redundancy
components are generally more vulnerable than fluid parts, the redundancy measures in fluid technology are focused on signal distribution . However, fluid systems may also have a redundant design. In doing
Force multiplication ratio
Since the pressure in a fluid is the same at every point (laws of hydraulics), the force generated is solely dependent on the size of the area on which the pressure is acting. It is possible therefore
Viscosity index (VI)
Characterises the Viscosity/temperature characteristic of a fluid. The smaller the change in viscosity with respect to temperature, the higher the VI (CETOP RP 100). The VI is mathematically calculated
Bar
Unit for pressure: 1 bar = 105 N/m2 The unit "bar" is frequently used in modern fluid technology, as that way the traditional numerical values can still be used for pressures. In SI units the unit "pascal"