초록 ▼

A tunnel freezer comprises an elongate tunnel which is inclined to the horizontal and which can be rotated about its longitudinal axis. The inside of the tunnel is provided with a weir which retains a pool of liquid nitorgen between the weir and the upper end of the tunnel. Particles to be frozen ar

A tunnel freezer comprises an elongate tunnel which is inclined to the horizontal and which can be rotated about its longitudinal axis. The inside of the tunnel is provided with a weir which retains a pool of liquid nitorgen between the weir and the upper end of the tunnel. Particles to be frozen are introduced into the tunnel on a conveyor and drop into the pool where they freeze substantially without aggregation. Rotation of the tunnel carries the particles out of the liquid nitrogen and through the remainder of the tunnel to the outlet end of the tunnel. The frozen particles and the nitrogen vapour from the tunnel pass through a common outlet which is provided with a pivoting plate which restricts the flow through the common outlet so that the tunnel operates at or slightly above atmospheric pressure thereby inhibiting ingress of moist air into the tunnel. Movement of particles through the tunnel is facilitated by lifting bars which form part of a liner which can be readily removed and replaced as desired. In a second embodiment the tunnel is provided with a spiral ribbon which forms a multiplicity of pools extending along the tunnel. This embodiment is particularly useful where the supply of frozen particles is variable.

대표청구항 ▼

A freezer comprising in combination an elongated tunnel having a generally cylindrical shape, said tunnel being adapted for inclination at an angle to horizontal; said tunnel having a first or inlet end and a second or discharge end; means to rotate said tunnel about its longitudinal axis; means dis

A freezer comprising in combination an elongated tunnel having a generally cylindrical shape, said tunnel being adapted for inclination at an angle to horizontal; said tunnel having a first or inlet end and a second or discharge end; means to rotate said tunnel about its longitudinal axis; means disposed adjacent said inlet end to trap and maintain a pool of liquid cryogen proximate said inlet end of said tunnel; means disposed along the length of the interior of said tunnel to enable product to be moved inside said tunnel from said inlet end to said discharge end; means to introduce said product into said pool adjacent said inlet end of said tunnel; and means to introduce liquid cryogen onto said product as it enters said tunnel and into said means to form said pool of liquid.