Calculate surface speed
The surface speed at the sealing point is one of the things that decides which design and which elastomer come into question. It follows from shaft diameter and speed.
Formula: v = π · D1 · n / 60 000 — with D1 in millimeters and n in revolutions per minute, v comes out in meters per second. The 40 m/s limit applies to VR rotary shaft seals, and not at the same time as the maximum pressure. We are happy to size your specific case.
What the surface speed affects
As the surface speed rises, so does the friction power at the sealing lip, and with it the temperature. That loads both the elastomer and the lubricant. The permissible speed therefore always depends on the interplay with pressure, lubrication and material — the 40 m/s is a limit, not an operating point.
Because VR seals work with a much lower radial force, less frictional heat is generated. That shifts the speed that can be reached in practice upwards. More on this under Friction power.
Further design parameters
- Pressure on the sealing side — up to 150 bar with design SOA
- Operating temperature — it determines the choice of material
- Medium to be sealed, and lubrication conditions
- Surface finish and hardness of the shaft
- Annular gap ds between shaft and support body
The requirements for these are in the Design guidelines.