New technology reduces freezers’ downtime
A recent advance in freezing technology has made it possible for manufacturers to improve productivity by reducing the downtime involved in defrosting their freezers.
By significantly increasing evaporator coil face area and evaporator fin cooling surface area, a new range of freezers provides frost with more places to build up. This is said to prevent frost from concentrating in one place, thus extending the time the freezer can run without defrosting.
On the new JBT FoodTech M-series of freezers, air leaving the evaporator is also very dry, since moisture is left on the evaporator fins.
Freezer run times are also extended by as much as three times by using an air defroster. With this technology, a shockwave of pressurised air is used to blow off the inlet face of the coil and remove frost.
Alternatively, by using a ‘mid-shift defrost’ during periods when lines aren’t running and the freezer is stopped, the ammonia refrigeration system is reversed to send hot gas instead of refrigerant to the evaporator. This quickly defrosts the evaporator while maintaining the rest of the freezer below freezing point.
A third option, available on JBT FoodTech’s Gyrocompact self-stacking spiral freezers and its FloFreeze individually quick frozen freezers, is to use sequential defrosters. These feature separate chambers, each with its own dedicated fan and evaporator, which provide spare capacity so that one evaporator and fan can be shut down to defrost while the other chambers continue to operate.
On the downside, however, freezers with sequential defrost cost more to buy and use more power to run.
