Maximum Gap Allowance

Maximum Gap Allowance

The dynamic diameter of a seal should be used. Cylinder diameter for a piston seal (D) and rod diameter for a rod seal (d).

Extend the connection lines between d/D-S and P-T to lines 1 and 2 respectively. Combine the two obtained intersections and read on these on the scale (example.1: 0,16 mm and example 2 : 0,18 mm) the allowable gap.

Operating conditions:

1. Surface quality should be according to recommendations

2. Pressure fluid should have proper lubricating qualities

For special conditions (e.g. non-lubricating fluids, water, acids, alkalis) please contact us.

Nomograms have been created for “worst case”-situations (i.e. pushing conditions) and softest material in the corresponding group (e.g. 85 Shore A for polyurethanes and 70 Shore A for NBR).

If the application is not in pushing conditions, the extrusion gap can be increased for 25%.

If the polyurethane seal is 93 Shore instead of the softer 85 Shore, or the NBR-seal is at least harness 85 Shore, then the extrusion gap can be increased 15%.