Mixer apparatus and method with improved shaft stub end seal structure

A mixer for mixing and processing materials comprising:

• a mixing chamber having a wall defining an inner space configured for receiving material to be mixed;
• an elongated rotatable mixing shaft extending through the chamber inner space, the shaft having a stub end and a drive end positioned proximate opposing ends of the mixing chamber;
• a non-rotatable stub shaft extending through an opening in the end of the mixing chamber and coupled to the chamber end for linear translation therethrough, the stub shaft being generally prevented from rotating in the chamber end;
• the stub end of the mixing shaft rotatably coupled to the stub shaft within the inner space for rotating in the mixing chamber without extending through the end of the chamber;
• a seal structure coupled between the stub shaft and the end of the mixing chamber for sealing the chamber inner space from the environment outside of the mixing chamber, the seal structure operable for moving with the linear translation of the stub shaft for maintaining the seal during such translation;
• whereby better product containment and process environment integrity is achieved in the mixing chamber.