Radial shaft sealing ring

A shaft seal for sealing a passage accommodating a rotary shaft in vacuum apparatus having a housing part, comprising:

• at least one annular sealing member having a lower high pressure side and an upper low pressure side and disposed in a housing part, the sealing member forming with the rotary shaft an upper annular chamber for accommodating a blocking liquid as a pool;
• the sealing member having between the low pressure side and the high pressure side a single sealing lip adjoining the annular chamber which is upwardly open to a vacuum chamber while the shaft is rotating normally;
• the sealing member and the rotary shaft having a central axis which runs in a vertical direction;
• and
• a blocking liquid of high molecular weight disposed in the annular chamber as a pool and having a total upper pool surface upwardly open to the vacuum chamber while the shaft is rotating normally, the blocking liquid of the annular chamber being pooled against the sealing member in contact with the vacuum chamber in such manner that the total upper surface of the pool of the blocking liquid has a direct contact with the vacuum chamber and is fully exposed thereto while the shaft is rotating normally.