A cryogenic tunnel freezer (10) having modular design and construction including a lower section (16) that can be raised and lowered relative to an upper section (14), the upper and lower sections (14, 16) defining a tunnel (12) when the lower section (16) is in a closed (raised) position. Product is moved through the tunnel (12) via a belt (22) formed of arrays of plastic modules (76) that are reinforced by metal chains (140) and rods (150). The lower run (23) of the belt (22) rides on the floor (48) of the lower section (16) and the upper run (21) rides on the lower run (23) when the belt (22) is operated. The flow of cryogenic fluid through the tunnel (12) is aided by vaporization of a cryogenic fluid and baffles (98), but no air-moving devices located within the tunnel (12).
