Labyrinthine mechanical seal

A mechanical seal in the bore of a casing for transferring high-pressure fluid with a rotatable shaft, said casing having at least one opening communicating with the bore thereof for conducting fluid under high pressure, bearing members having radial clearances mounting said shaft substantially free of an axial force to extend within the bore of said casing for axial movement in said casing, said shaft having a central bore extending between radial and spaced-apart fluid openings, the combination therewith of:

• a first group of discs arranged in spaced-apart relation along said rotatable shaft,
• means including spacers between the discs of said first group of discs for clamping the discs to said rotatable shaft,
• a second group of discs arranged in a non-rotatable manner at spaced-apart locations in the bore of said casing to extend around said shaft and mesh with discs of the first group in the manner of a labyrinth,
• means including spacers between the discs of said second group for clamping such discs to said casing in the bore thereof, the axial mobility of said shaft being limited only by an 0.2 millimeter or less clearance defined by said spacers between the discs of said first and second groups of discs and the radial clearance between said spacers and discs being only slightly greater than the radial clearance in said bearing means for decreasing the pressure of any fluid between consecutive discs to minimize fluid loss, each of said means having alignable openings to conduct high-pressure fluid between a radial fluid opening of the shaft and the opening in the casing in a direction radially between discs of said first and second groups of discs.