Spiral Freezer

Overview

A spiral freezer freezes product continuously while taking up little floor space, by running a long conveyor belt up a tall helix inside a cold box. The Spiral Conveyor wraps its belt around a rotating drum cage so a long dwell fits in a small footprint; the Evaporator blasts cold air across every tier; the Refrigeration System supplies the cold; the Defrost System clears coil frost; and the Control System holds air temperature and belt speed. It all lives inside the insulated Insulated Enclosure on a stainless Support Frame.

How it works

The trick of a spiral freezer is fitting a long freezing time into a small building. Freezing takes minutes, and at any reasonable belt speed a straight conveyor would need to be enormously long; the Spiral Conveyor solves this by stacking the belt in a helix many tiers tall around a Drum Cage. The cage turns, and its Cage Drive Bar drive bars grip the belt edge and carry it up by friction, driven by the Cage Drive through its Drive Gearbox. A Belt Take-up take-up absorbs the belt's contraction as it chills.

Cold comes from a vapour-compression loop. The Compressor raises refrigerant pressure, the Condenser sheds that heat outside, the Expansion Valve drops the pressure, and the refrigerant boils in the Evaporator Coil, chilling the recirculated air. The Evaporator Fan units drive that air horizontally across the spiral at high velocity, since fast-moving cold air pulls heat out of product far quicker than still air. Moisture from the product freezes onto the coil over a run, choking airflow, so the Defrost System periodically energises its Heating Element heaters to melt the frost, draining to the Drip Pan. The whole space is held by the Insulated Enclosure of insulated panels with heated-frame doors so seals do not ice shut, and the Control System runs the refrigeration loop, sets belt speed for the freezing time, and sequences defrost.