Dynamic rotary shaft seal for mixing apparatus

A method for installing a seal for sealing a gap between rotatable shaft and a vessel wall where the rotatable shaft penetrates the vessel wall, the method comprising:

• fixing an adapter plate non-rotatably with respect to the vessel wall, the adapter plate having a forward face oriented toward the vessel wall, a rearward face opposite the forward face, and a central bore alignable with the rotatable shaft;
• placing a stator plate with a central bore, a forward face, and a rearward face, the stator plate being placed rearwardly with respect to the adapter plate and mounting an adapter-stator sealing member between the rearward face of the adapter plate and the forward face of the stator plate;
• non-rotatably fixing an interfacing boot with respect to the rotatable shaft to rotate therewith, the interfacing boot having a central bore aligned with the rotatable shaft, the interfacing boot being disposed rearwardly with respect to the stator plate and having a forward face, a rearward face, and a lip extending circumferentially about the forward face of the interfacing boot, the lip encircling the central bore and protruding forwardly from the forward face of the interfacing boot, the lip being in sliding contact with the stator plate when the rotatable shaft rotates, and the lip configured so that the lip may be displaced by an axial misalignment of the rotatable shaft while the lip maintains contact with the stator plate;
• non-rotatably attaching a central boot with respect to the rotatable shaft to rotate therewith, the central boot having a forward face, a rearward face, and a central bore;
• attaching a drive ring to be axially movable and non-rotatable with respect to the rotatable shaft, the drive ring having a forward face, a rearward face, and a central bore, the rearward face of the drive ring being disposed rearwardly with respect to the rearward face of the central boot, and placing the drive ring so that third engagement features thereof, the third engagement features being configured to engage the drive ring non-rotatably with respect to the central boot, engage the second engaging features of the interfacing boot;
• the drive ring configured to bear urge the central boot forwardly when the drive ring is urged axially forwardly;
• attaching an anchor ring having a forward face, a rearward face, and a central bore to be non-rotatably fixed and axially movable with respect to the drive ring;
• operatively securing a bias member with respect to the anchor ring and the drive ring to urge the anchor ring and the drive ring axially apart;
• securing a compression member to compress the bias member so that upon release of the compression member, the bias member urges the drive ring and the anchor ring away from each other;
• placing the anchor ring and the drive ring on the rotatable shaft with the drive ring engaged with the central boot;
• and
• securing the anchor ring to be axially and non-rotatably fixed with respect to the rotatable shaft to prevent axial movement and relative rotation with respect to the rotatable shaft, and then releasing the compression member so that the compression member urges the drive ring forwardly with respect to the anchor ring.

A seal for sealing a gap between rotatable shaft and a vessel wall where the rotatable shaft penetrates the vessel wall, the seal comprising:

• an adapter plate adapted to be non-rotatably fixed with respect to the vessel wall, the adapter plate having a forward face oriented toward the vessel wall, a rearward face opposite the forward face, and a central bore alignable with the rotatable shaft;
• an adapter-stator sealing member mounted to protrude rearwardly from the rearward face of the adapter plate;
• a stator plate with a central bore, a forward face, and a rearward face, the stator plate being disposed rearwardly with respect to the adapter plate, the stator plate being in contact with the adapter-stator sealing member protruding from the rearward face of the adapter plate, and the stator plate being non-rotatably attached with respect to the adapter plate and attached in a manner permitting the stator plate to tilt angularly with respect to the adapter plate;
• an interfacing boot, the interfacing boot having a central bore alignable with and fittable to the rotatable shaft, the interfacing boot being non-rotatably fixable with respect to the rotatable shaft to rotate therewith, the interfacing boot being disposed rearwardly with respect to the stator plate and having a forward face, a rearward face, and a lip extending circumferentially about the forward face of the interfacing boot, the lip encircling the central bore and protruding forwardly from the forward face of the interfacing boot, the lip being in sliding contact with the stator plate when the rotatable shaft rotates, and the lip having a forward surface and the forward surface being smaller radially than the stator plate so that the lip may be displaced by an axial misalignment of the rotatable shaft while the lip maintains contact with the stator plate, and a radial wall extending into the central bore;
• a central boot having a forward face, a rearward face, and a central bore and being non-rotatably fixable to the rotatable shaft to prevent relative rotation with respect thereto, the forward face of the central boot being disposed rearwardly with respect to the radial wall of the interfacing boot, the central boot having a plurality of first engagement features for engaging corresponding second engagement features of the interfacing boot, the first engagement features and the second engagement features being configured to engage and thereby prevent relative rotation between the interfacing boot and the central boot while allowing relative axial movement between the interfacing boot and the central boot, the central boot being configured so that the radial wall of the interfacing boot prevents the central boot from passing axially forwardly through the interfacing boot when the central boot moves axially with respect to the interfacing boot;
• a drive ring having a forward face, a rearward face, and a central bore and being non-rotatably fixable with respect to the rotatable shaft to prevent relative rotation with respect thereto, the rearward face of the drive ring being disposed rearwardly with respect to the rearward face of the central boot, the drive ring having third engagement features configured to engage the drive ring non-rotatably with respect to the central boot, and the drive ring having a radial wall configured to bear against the central boot to urge the central boot forwardly when the drive ring is urged axially forwardly;
• an anchor ring having a forward face, a rearward face, and a central bore and being non-rotatably fixable with respect to the rotatable shaft to prevent relative rotation with respect thereto, the anchor ring being configured to be selectively axially movable and selectively axially fixable with respect to the rotatable shaft, the anchor ring further being non-rotatably fixed and axially movable with respect to the drive ring;
• a bias member configured to urge the anchor ring and the drive ring axially apart;
• and
• a compression member configured to be secured to compress the bias member and configured to be released so that the bias member urges the drive ring forwardly with respect to the anchor ring.