Freezing tunnel cold-gas extraction hoods with variable-opening extractors

Abstract

An installation for cryogenic cooling or freezing of products includes: a cryogenic tunnel through which products that are to be cooled or frozen circulate, between an entrance into the tunnel and an exit from the tunnel on a conveyor belt; an upstream extraction hood situated facing the entrance to the tunnel and/or a downstream extraction hood situated facing the exit from the tunnel; and movable blinds or shutters that make it possible to close all or part of a suction cross section of at least one of the said hoods over a width and depth of the conveyor belt.

1 - 4 . (canceled) 
     
     
         5 . An installation for the cryogenic deep-freezing or cryogenic cooling of products, comprising:
 a cryogenic tunnel through which the products to be deep-frozen or cooled circulate between an entrance into the tunnel and an exit from the tunnel, the tunnel being equipped with spray lines for injecting a cryogenic fluid into the internal space of the tunnel in which the products circulate with the aid of a conveyor belt;   an upstream first extraction hood situated facing the entrance to the tunnel and/or a downstream second extraction hood situated facing the exit from the tunnel; and   movable blinds or shutters for adjusting a cross section of at least one of said hoods across a width of the conveyor belt and over a depth of the conveyor belt by blanking off all or part of said cross section.   
     
     
         6 . The installation  claim 5 , wherein
 the movable shutters or blinds can be actuated in a parallel manner, generating, after blanking, a rectangle in the cross section of at least one of the hoods; and   the movable shutters or blinds can be actuated in a non-parallel manner, generating, after blanking, one or two triangles in the cross section of at least one of the hoods.   
     
     
         7 . The installation of  claim 5 , wherein each hood is equipped with an extraction tube leading to the outside, connected in its middle to the top of the hood. 
     
     
         8 . The installation of  claim 5 , wherein each hood is equipped with at least one extraction tube leading to the outside, at least one of the hoods having its tube(s) connected to one side of the relevant hood.