Freezer spacers – how do they work and what are the differences
As for most product categories also Freezer-spacers come in a variety of designs. As such it is not always easy to weigh the actual differences in-between these and clearly determine which ones are best suited for your operation.
Obviously the overall purpose of using spacers is to create space in-between the stacked layers.
This is to transport the heat from the content within the stacked boxes – especially in the middle of the stacks where the cooled air otherwise would have limited contact. Let’s define this function as “heat-transfer”.
High air velocity across the product and maximum contact between the cold, high-velocity air stream and the product – in our case the stacked boxes – are both essential for high efficiency.
As such an even more important spacer-function is to ensure that the cold air-stream is not blocked after the first few pallets but with the highest possible velocity also reaches the pallets in the far end of the freezing chamber. This function is defined as “air-flow”.
High air-flow throughout the freezing-chamber is an extremely important driver for the overall efficiency of the freezing process as the total batch-freezing time, after all, is determined by the “last sheep in the flock”. If the velocity of the air-stream has dropped considerably after the first few pallets (which is not unusual) it’s easy to imagine how much “energy” there is left for the “heat-transfer” from the pallets at the far end of the freezing chamber. Consequently, you risk wasting lots of energy in your cooling system, fans, and evaporators.
Factors influencing freezing time
Accordingly, it is important for the efficiency of a spacer that air is not confined within the spacer in-between the stacked layers but that the spacer is designed in a way that allows a high air-exchange. At Neptun Freezer Spacers we believe in a 50 mm high, open profile spacer design – simply because this has proven its superior efficiency.
Arranging the pallets in the freezing chamber
In order to minimize that air is “caught” in-between the individual pallets, we also recommend that the pallets are placed close to each other as possible – thereby “forcing” the airstream to pass through the pallets rather than to turbo-lice in-between these.
..is as important as efficiency. After all – if the benefits do not exceed the drawbacks you would probably not use spacers at all.
Functionality is determined by various factors such as
- Support of the stacked boxes
- Easy to clean
- Anti-slip surface
- Cost and life-time
As there are big differences in blast-freezing operations and the way spacers are applied the importance of the above features varies. Hence it is important that the spacers efficiency and the above features are prioritized, evaluated and rated individually when investing in spacers.