Mineral oils
Most commonly used form of hydraulic fluid (" oil hydraulics "). Their high level of lubricity and relatively high viscosity make it possible to use gap seals in pumps and valves and therefore choose a
Oil cooler
cooler : The oil flow passes through pipes with turbulence inserts to increase heat transfer. The fluid in these pipes flows in the opposite direction to the cooling water ( Figure O 4 ). Air-cooled oil
Flow resistance of filters
grade , the flow rate, the filter surface area and design as well as on the viscosity of the pressure fluid and therefore on its actual temperature (Figure F 13) . As the pressure drop is not linear, but instead
Internal gear pump
in most cases whose outer (ring gear) has teeth on the inside. The inner sprocket is smaller. The fluid is conveyed in the spaces between the gaps in the teeth of the two gear wheels. Thanks to a long contact
Hydromechanical efficiency
assembly, M Δp = losses due to pressure difference (friction and jamming forces), M ν = losses due to fluid friction and M ρ = flow losses. These give a total loss torque M V With hydraulic pumps, this loss
Flow in gaps
a symmetrical velocity profile will form ( Figure S 101 a ), which is caused by adhesion of the fluid to the surface. The flow rate/pressure characteristic is described by Hagen-Poiseuille's law ( Circular
Viscosity/temperature characteristic
The viscosity of a Newtonian fluid changes as a factor of the temperature: For hydraulic fluids it decreases rapidly as the temperature rises and at low temperatures it approaches the pour point ( Figure
Hydraulic fluids
spool areas as well as the surfaces against corrosion. As it flows through the system, the hydraulic fluid conducts away the locally occurring heat and takes with it contamination, which is caused by debris
Solenoid actuation
Actuation of a fluid-based device by a solenoid with a stroke that is transferred directly to the device and triggers there an actuation (e.g. switching directional valve ) (Figure E 24) . In this way
Filter installation
undertaken in the secondary flow (f) , as a separate circuit is selected in which a pump presses the fluid through the filter independent of the working cycle, as well as mostly through a cooler .