Formax, Inc.

Chase Brass and Copper Company, LLC

James E Johnson

Glenn A Sandberg

Robert C Ruhl

Michael W Morgan

A cryogenic food product freezing tunnel comprising a stationary structure including an entrance end housing section, a tunnel housing cover, and an exit end housing section, a conveyor to transport food products through the tunnel housing, a spray header to spray a liquid cryogen onto the food products near the exit end of the tunnel, and an exhaust plenum to exhaust cryogen gas from the entrance end. The base of the tunnel housing is a series of U-shaped modular units arranged end-to-end and suspended from the stationary structure by individual hydraulic elevators, movable between a lowered, open service position and a raised position sealed against the housing cover and the end housing sections. Each end base unit is lowered outwardly and downwardly to its service position and is raised along the same path; the base units are lowered in predetermined sequence, end units before center units, and are raised in the reverse sequence. The base units are held sealed to the stationary structure by constant pressure applied by the elevators, using double-bulb silicone gaskets with bonded polyfluoroethylene coverings. Each base unit includes plural sub-modules joined by shielded external expansion slip joints with a continuous interior sheet metal covering. The cover is of modular construction with polyfluoroethylene coated silicone gaskets of clothes-pin configuration between modules. The spray header is a large tube with liquid discharge nozzles below and gas relief nozzles above; excess liquid cryogen is collected in a very long pan below the header and the upper run of the conveyor belt is guided down and up very mild inclines to skim the surface of liquid cryogen in the pan. Insulated doors on the ends of the tunnel and an automatically controlled exhaust damper permits standby for extended periods. The conveyor belt supports are also of sub-modular construction.

Cryogenic freezing tunnel

Level winding is accomplished by rotating a reel with sufficient torque to wind material on the reel while traversing the reel a predetermined precise fractional part of the width of the material wound for each increment of revolution of the reel so that the reel is traversed precisely the width of the material wound plus a precise space between adjacent turns, if desired, during each revolution of the reel. Pulses indicative of the extent of rotation of the reel are transformed, by dividing, into pulses indicative of both the extent of rotation of the reel and the desired distance between centers of adjacent turns of the material wound onto the reel. The pulses rotate a first synchrotransducer electrically connected to a second synchrotransducer which is driven in response to traverse of the reel. An error signal resulting from any non-synchronism of the synchrotransducers is used to operate a servo-valve which changes the rate of traverse in a direction to reduce the error signal.

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Southfield, MI, United States of America

James E Johnson