There is no chance for a labyrinth seal to protect against any pressure gradient between both sides of the seals. Pressure gradients may be reduced but not sealed.
There is also no chance for a labyrinth seal to protect against higher liquid levels. Any liquids level reaching the level of the gap could pass the seal easily. For this reason care has to be taken for sufficient drain holes or anything adequate in order to avoid any liquid levels in front of the seal.
Not generally: Positive air improves the sealing efficiency, but air consumption is very high! Care has also to be taken when the air is applied through the grooves of our M-type seal because the applied air stream finds its way in both directions: To the outside area and also in direction of the bearing! There is a certain risk that the bearing could be dried with the applied air stream - the result would be a very limited lifetime of the bearing.
Absolutely: Spacers are protecting the gap from direct contamination and so the efficiency of the seal is improved especially in low-speed applications. For this reason a spacer is recommended generally.
In this case we always recommend a gap-seal type "S pre-greased". The gap is filled completely with grease before the assembly of inner- and outer ring. The fat pad could seal little dust particles quite reliably. When running little grease beads are created on both sides of the gap.
Basically this is the very best solution - but of course it is also the most expensive one and it needs much more space.
There must be a sufficient space in between (minimum width 5 mm) and of course a corresponding drain hole.
Only with an additional positive air (sealing air).
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