Shut off seal about a shaft of a device having a side entry into a tank

A shut off seal in a device having a rotatable shaft extending through a nozzle side entry structure of a tank, comprising:

• a mounting flange attachable to the nozzle structure;
• a housing about the shaft, the housing having a flanged end which is releasably attachable to the mounting flange and which is sized to enable it to enter the nozzle structure, said flanged end having a flat outer surface;
• releasable attachment means for attaching the flange of the housing to the mounting flange;
• sealing means between the mounting flange and the housing;
• packing about the shaft within the housing, the packing providing a seal about the shaft and lubricating the shaft when it is rotating;
• a collar having a sealing ring at one end thereof, the collar being attached to the shaft with the sealing ring facing the flat outer surface of the flanged end of the housing, the collar being spaced slightly from the housing when the housing is attached to the mounting flange;
• and
• means for sliding the housing into engagement with the sealing ring of the collar so that the sealing ring and the flat outer surface of the flanged end of the housing form a seal about the stationary shaft while also maintaining the seal between the mounting flange and the housing.