Oil sampling
the system and not lend themselves to comparison with others. Apart from absolute cleanliness for all devices coming into contact with the fluid to be sampled, these guidelines also stipulate the correct [...] e distribution of solid particles is likely to be found. The valve required for removal purposes should be attached in the direction of the flow and without using any pipe between ( Figure O 7 ). [...] The oil samples needed to check the degree of contamination of hydraulic fluids must be taken in compliance with highly specific guidelines or the measurement results will not be representative for the
Flat seals
Collective term for seals with a low height compared to the sealing surface and that adapt to the sealing surface over their entire width. They therefore generally have a more or less rectangular cross [...] also flat seals. Flat seals are made from almost all materials suitable for seals: Metals with or without padding and non-metallic materials, such as rubber, PTFE, It, asbestos substitute and others. Flat
Hydraulic intensifier
makes it possible to operate a differential cylinder in a network with impressed pressure ( constant pressure network ) without experiencing pressure losses due to throttles, and to feed energy back under [...] certain conditions. To this end, the pressure level in the network is transformed, via a combination of a hydraulic motor subject to secondary control and a fixed displacement motor , to the pressure level [...] accordance with its load at that moment. The fixed displacement motor is linked with the motor subject to secondary control and thereby removes the flow rate for the cylinder from the pressure network like
Reversing motor
be changed, without changing the direction of the absorbed volume flow by moving the lifting element away from zero. Reversing motors are rarely used (exception: hydraulic motors subject to secondary control)
Action of multiple resistance
pipes, that a Δp of 8 to 10 bar is easily created. Parallel resistances result in a flow division, wherein the flow in the individual branches is inversely proportional to the resistance to be overcome ( parallel [...] This means, for example that a synchronisation of multiple cylinders is practically impossible without auxiliary equipment.
Energy losses in hydraulics
31) : pressure losses in lines due to friction and flow deflection, pressure losses in valves as well as accessories, such as filters and coolers , Pressure losses due to throttling , which on constant pressure [...] absorbed by the oil and housing. On systems without appreciable throttling approx. 15 % can be expected on average, while in throttle circuits the loss element can be 25 to 30 % and higher.
Impressed pressure
pre-charged to the nominal pressure of the system. As on the hydropneumatic accumulators used today the accumulator pressure drops on the drawing usable volume (corresponds to the ratio of gas capacity to usable [...] The change in pressure in a hydraulic system without throttling or storage corresponds to the related change in load pressure (taking into account the pressure losses ). On accumulator supplies , however
Frequency limit
case from the occurrence of a correctly functioning input configuration to the output of the related output configuration, referred to a defined signal processing procedure (DIN 19 237). Frequency limit of [...] Highest frequency of a periodic signal at which the signal is still just processed without errors. Frequency limit of a signal component : Inverse of the sum of the minimum pulse duration and the minimum
Starting performance of hydraulic motors
Behaviour of a hydraulic motor on transition from standstill to motion. Due to its design and the related friction and leakage losses, during starting a motor outputs a significantly lower useful torque [...] of a hydraulic motor is characterised by its starting torque , the pressure required on stating without load as well as the magnitude of the starting jerk (= speed jump) and the lowest rotation speed (slow [...] t leakage oil flow . The starting behaviour of slow speed high torque motors is generally superior to that of high speed motors .
Methods of valve installation
is mounted on a manifold that contains all the necessary ports such that it is possible to replace a valve without dismantling the pipe. The manifolds may also be suitable for stacking. Plug-in designs