Force density
conclusions regarding the compactness of various types of drives offering the same power ( Table K 1 ).
Darcy friction factor λ
and dynamic pressure related to the circular cross section, when flowing through a straight of length 1 and diameter d. λ depends on the Reynolds number and the surface roughness of the pipe: for laminar
Beta value (β value)
with a specific pressure drop (Figure B 13) : Therefore at β x = 1 no particles are removed; 50 % of the particles are removed at β x = 2. The minimum practical value aimed for today β x = 75 then means
Residual oil content (PN)
Occasionally, it will also be stated in ppm (weight unit of oil per million weight units of air): 1 ppm ≈ 1.2 mg/m3.
Noise level L W
the entire sound power W emitted from an acoustic radiator in relation to a specific output W o of 1 pW. The sound power level is therefore a machine-specific variable, which is used by machine operators
Buckling of rams
buckling) In addition to the basic scenario (scenario 1), another three buckling scenarios are possible in this context (Figure K 12). Mounting scenario 2 applies in most cases, so that s = l. Particularly
Air in oil
1. Providing the air is dissolved in the oil, it will not affect its characteristics. 2. Undissolved air, i.e. bubbles, cause the following: signs of corrosion on pumps and controls, increased compressibility
Accumulator regulations
product p · l <200) and which in group III (200 < p · l ≦1 000) is undertaken at the manufacturer. Vessels with a pressure-litre product above 1 000 must be inspected by TÜV at the operating organisation
Thin foil element
and sealing element that, as a consequence of the very low mass, permits switching times of 0.2 to 1 ms (Figure F 33) . Even though the thin foil element is switched by a static pressure signal or differential
Digital cylinders (with several positions)
mostly binary tiered pistons that can be operated in any combination. Therefore with n pistons 2n-1 positions are obtained with a positioning accuracy that is only dependent on the manufacturing accuracy