Abstract: Track jumping in the present system is accomplished by using a two step track jump method which accelerates the tracking actuator toward the desired track at maximum acceleration and then decelerates the tracking actuator at a maximum deceleration so that the desired track is reached in a minimum amount of time without the actuator ringing. A matrix containing the times for each jump pulse from track X to track Y is recorded. The matrix table is updated after each jump to compensate for variance factors. The table is stored in memory which allows the system to become more accurate with each jump. If the actuator falls short of the desired position, the jump pulse next applied is lengthened slightly. If the jump pulse causes the actuator to overshoot, the desired position the jump pulse is shortened for the next jump.

Abstract: The present method operates upon an optical disk type servo-system of the type having an optical tracking servo for maintaining a lens centered over a track on a disk and a tracking position servo for moving an optical head's lens to a desired position. Included within such a system is an eccentricity sub-system for providing a compensating sine wave signal for reducing errors in tracking due to disk decentering. The present method automatically adjusts the gain in one of the servos to match the gain appearing in the other servo so as to improve the smoothness of control when switching between the servos.

Abstract: A focus acquisition servo system and method which speeds the acquisition process by focusing on the recording media of an optical disk while the disk is coming up to speed. Focus is accomplished by jumping the focus actuator from a start position close to the focus position and by ramping the focus actuator away from the surface of the disk while monitoring focus gain. When the focus gain reaches a peak amplitude the disk is in rough focus, ramping is stopped and the focus servo system is activated to lock the focus actuator onto a fine focus on the disk's recording media.

Abstract: In order to reduce heat transfer from one side of a folding fire door lead post assembly to the other side, the lead post assembly includes a central lead post which forms the leading edge of the assembly. In one embodiment of the invention, wing panels extend from the sides of the central lead post and the receiving recess for the door when in closed condition is adapted to receive the central lead post and adjacent portions of the wing panels so that no portion of the central lead post is open to a room on either side of the door when the door is in closed condition. Heat transfer is from one wing panel to the central lead post to the other wing panel rather than directly from the fire to the central lead post. In a second embodiment of the invention, lead post side extensions are secured to the central lead post with heat insulating material therebetween.

Abstract: A fermentation vessel comprises an outer shell, and an annular draft tube located within the shell and spaced therefrom to promote continuous circulation of fluids through said draft tube within said shell. The draft tube has an internal cavity located within its walls. The cavity is connected to a fluid supply conduit that extends externally of the shell. A plurality of discrete nozzles are disposed about the circumference of the tube and communicate with the cavity to permit egress of fluids from the cavity to the interior of the shell to promote circulation.

Abstract: In order to reduce heat transfer from one side of a folding fire door lead post assembly to the other side, the lead post assembly includes a central lead post which forms the leading edge of the assembly. In one embodiment of the invention, wing panels extend from the sides of the central lead post and the receiving recess for the door when in closed condition is adapted to receive the central lead post and adjacent portions of the wing panels so that no portion of the central lead post is open to a room on either side of the door when the door is in closed condition. Heat transfer is from one wing panel to the central lead post to the other wing panel rather than directly from the fire to the central lead post. In a second embodiment of the invention, lead post side extensions are secured to the central lead post with heat insulating material therebetween.

Abstract: A transducer head, held in a fixed position as a preformatted disk is rotated a full revolution, reads any sector address accessible to the head. The addresses read come from a plurality of track revolutions that depend on the magnitude of the eccentricity of the disk. A computer, programmed with a least squares algorithm, first coordinates (1) data corresponding to the angular position of the disk each time an address is read, with (2) data corresponding to the actual radius of each address.