Allg. Einbauregeln
Even an optimally chosen seal must be properly installed according to its particular nature in order to ensure maximum functionality and a satisfactory operating life span. Therefore, we recommend adherence to the following basic rules:
Seals cannot take on a guiding function. Therefore, use separate guiding elements made of suitable materials. Shear forces are very damaging to seals. Therefore, the stronger the shear forces on rod and piston, the better the guiding elements must be. Seals should be installed as close as possible to the guides, in order to avoid damage caused by jamming of the piston. Lips and seal body must not be damaged. Therefore, if the seal is pushed over sharp edges during installation, use Einbauschrägen of approx. 15-20° with a width of at least half of that of the seal.
Warm large seals for snapping installations (such as cylinder sealing rings, groove rings and so on) in hot oil of up to 100°C before installation. If necessary, additional milling will make them smoother.
Normally, seal elements should not slide over gaps or drillings under pressure. The clearance between the moving parts must be kept sufficiently small, so that the seal cannot move into the resulting gap. Supporting and cover elements (e. g. Backringe) will help. Surfaces which get into contact with seals should not have any sharp edges. Smooth these surfaces using suitable finishing techniques.
The returning piston rod is a main cause of oil contamination. Therefore, the dirtier the working atmosphere of the cylinder, the more important are wipe rings.
Precautions must be taken which limit the dissolution of air within the hydraulic fluid. Therefore, among others, careful filling and ventilating before putting into operation is necessary.
Make sure that the flow of liquid is not restricted close to the seals, because this will cause a constant release of air which can destroy the seal.
When choosing the respective type of seal as well as the most suitable material, carefully observe the manufacturers’ recommendations. A strict adherence to the manufacturer’s installation instructions including installation spaces is of equal importance.
In this context particular attention should be paid to the following:
- Observe the groove dimensions. Otherwise the seal can either not “breathe” or it does not receive enough bias
- Installation with the biased side towards the pressure direction. This is especially important for compact piston seals, where the biased side may be difficult to recognize.
- Insufficient clamping together of elements in the sealing area of pistons can lead to a destruction of the seals.
- If necessary, use assembly aids for the installation of the seal. Considering the importance of seals for the safety of a hydraulic system, if necessary we recommend to take advantage of our technical consulting service which is free of charge for all our clients.
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