Axial circular sealing gap:
Gap created when a piston runs inside a bore (e.g. pump pistons, valve control spools in valves). Providing a centric gap is involved, the leakage will depend on the following (Figure K 37 a):
where
d B = bore diameter
d K = piston diameter
d m = average diameter
h = gap or half the diameter tolerance.
With an eccentric circular sealing gap, it is case of: (Figure K 37 b)
If the piston is positioned to one side, the leakage flow will increase 2.5 times. Radial circular sealing gap:
Gap created between, for example, the end of a cylinder drum for an axial piston pump and the control disc. Here, the leakage is as follows (K 37 c):
where
Figure K 37: a) Axial centric circular sealing gap, b) axial circular sealing gap, c) radial circular sealing gap