Method of and apparatus for the cooling of articles or materials

Claim 1

A method of cooling objects which comprises: (a) passing said objects through a cooling chamber in one direction; (b) introducing a first cooling-gas stream into said chamber at a relatively upstream location and passing said first cooling-gas stream in direct heat-exchange relation with said objects; (c) generating a second cooling-gas stream by evaporation and expansion of a liquefied gas and passing said second gas stream in direct heat-exchanging relation with the precooled objects at a location downstream from said upstream location; (d) withdrawing said second gas stream from said downstream location after at least partial heat exchange between said second gas stream and said objects; (e) passing said first cooling-gas stream in indirect heat exchange with a coolant other than said gas streams prior to the introduction of said first cooling-gas stream into said chamber at said upstream location; (f) mixing the withdrawn second gas stream with said first gas stream prior to its indirect heat exchange with said coolant; and (g) venting a portion of said first cooling-gas stream from a warm end of said upstream location corresponding to the quantity of said second cooling-gas stream introduced into said downstream location.

Claim 2

A method of cooling objects which comprises: (a) passing said objects through a cooling chamber in one direction; (b) introducing a first cooling-gas stream into said chamber at a relatively upstream location and passing said first cooling-gas stream in direct heat-exchange relation with said objects; (c) generating a second cooling-gas stream by evaporation and expansion of a liquefied gas and passing said second gas stream in direct heat-exchanging relation with the precooled objects at a location downstream from said upstream location; (d) withdrawing said second gas stream from said downstream location after at least partial heat exchange between said second gas stream and said objects; (e) passing said first cooling-gas stream in indirect heat exchange with a coolant other than said gas streams prior to the introduction of said first cooling-gas stream into said chamber at said upstream location; (f) mixing the withdrawn second gas stream with said first gas stream prior to its indirect heat exchange with said coolant; and (g) venting a portion of said first cooling-gas stream from a warm end of said upstream location corresponding to the quantity of said second cooling-gas stream introduced into said downstream location.

Claim 6

An apparatus for the cooling of objects, comprising: a horizontal cooling tunnel forming a cooling chamber; means for displacing objects progressively through said chamber in one direction from an upstream location constituting a precooling zone in said chamber to a downstream location constituting a deep-cooling zone of the chamber; a first conduit connected to said upstream location of said chamber for admitting a first cooling-gas stream to said chamber and passing said first cooling-gas stream in direct heat exchange with said objects at said upstream location to precool said objects; a second conduit connected to a source of liquefied gas and communicating with said downstream location of said chamber for admitting a second cooling-gas stream to said downstream location to flow in direct heat exchange with the precooled objects to finish-cool the same; a spray device having a plurality of nozzles spaced in the direction of displacement of said objects for spraying said liquefied gas on said objects, said liquefied gas vaporizing in said deep-cooling zone to constitute said second gas stream into said downstream location; a closed-cycle refrigeration unit having an evaporator connected to said first conduit for the indirect cooling of said first gas stream prior to its admission to said upstream location; and an outlet connected to said downstream location and delivering a second cooling gas upon at least partial warming thereof in heat exchange with objects in said downstream location to said evaporator for mixture with said first gas stream prior to its passage into indirect heat exchange with said evaporator.

Claim 7

An apparatus for the cooling of objects, comprising: a horizontal cooling tunnel forming a cooling chamber; means for displacing objects progressively through said chamber in one direction from an upstream location constituting a precooling zone in said chamber to a downstream location constituting a deep-cooling zone of the chamber; a first conduit connected to said upstream location of said chamber for admitting a first cooling-gas stream to said chamber and passing said first cooling-gas stream in direct heat exchange with said objects at said upstream location to precool said objects; a second conduit connected to a source of liquefied gas and communicating with said downstream location of said chamber for admitting a second cooling-gas stream to said downstream location to flow in direct heat exchange with the precooled objects to finish-cool the same; a spray device having a plurality of nozzles spaced in the direction of displacement of said objects for spraying said liquefied gas on said objects, said liquefied gas vaporizing in said deep-cooling zone to constitute said second gas stream into said downstream location; a closed-cycle refrigeration unit having an evaporator connected to said first conduit for the indirect cooling of said first gas stream prior to its admission to said upstream location; and an outlet connected to said downstream location and delivering a second cooling gas upon at least partial warming thereof in heat exchange with objects in said downstream location to said evaporator for mixture with said first gas stream prior to its passage into indirect heat exchange with said evaporator.