Cold chain: conveyors in refrigerated facilities
Which belts withstand -30 °C, how to design conveyors for freezing lines and cold stores — materials, lubrication and construction.
A conveyor in a refrigerated facility works in conditions where ordinary equipment fails fast: frost down to -30 °C, condensation, ice build-up, thermal shock at zone entries and exits. In this article we break down how we design conveyors for the cold chain — from belt choice to bearing lubrication.
Why cold destroys an ordinary conveyor
Low temperature changes the properties of all materials. Polymers become brittle, rubber loses elasticity, lubricant thickens, metal grows more sensitive to impact loads. A conveyor designed for a room-temperature workshop cracks at the belt, seizes at the bearings and stalls the drive in a freezing chamber.
A separate problem is condensation. Product entering the freezing zone warmer gives off moisture, which settles on the belt and frame and freezes. Ice build-up increases the load on the drive and distorts the route geometry.
Another hidden factor is thermal expansion. Metal and polymers contract when cooled, and at different rates. If the structure is designed without accounting for this, stresses arise at unit joints, play appears or, conversely, jamming. So we calculate a cold chain conveyor as a system working across a wide temperature range, not at a single temperature.
Belts that withstand frost
Not every belt material is suitable for the cold chain. Standard PVC already loses flexibility at -10 °C. For freezing we choose materials with a confirmed low-temperature range.
| Belt material | Working minimum | Cold chain application |
|---|---|---|
| PVC | -10 °C | unsuitable for freezing |
| Polyurethane (PU) | -30 °C | cooling, light freezing |
| Modular POM | -40 °C | blast freezing, tunnels |
| Modular PP | -20 °C | cold stores |
| Stainless steel mesh | -60 °C | spiral freezers |
For blast freezing and spiral freezers, modular POM belts or stainless steel mesh belts are optimal — they keep their strength even at -40 °C and below.
Drive, bearings and lubrication
In the cold, standard lubricant thickens and stops doing its job. For the bearings of cold chain conveyors we use low-temperature synthetic-based greases rated for operation down to -50 °C. We place the drive outside the freezing zone or choose a version in a frost-resistant housing. The protection class is no lower than IP65: condensation and periodic thawing demand sealing.
Engineer’s tip. Most cold chain problems come not from the freezing zones themselves but from the transitions between warm and cold environments. That is where condensation, thermal shock and icing occur. On such sections we provide drainage, air blow-off or heating of critical units and do not save on stainless steel — galvanised steel in a condensation zone rusts within a season.
Servicing a conveyor in the cold
A cold chain conveyor is harder to service than an ordinary one: personnel work in the freezing chamber for a limited time, and any stoppage of the freezing line is a risk for the product in the zone. So we design such conveyors with quick maintenance in mind: units needing attention are moved into accessible zones, fasteners are made for standard tools, and critical parts are duplicated in the spare-parts kit. The less time a mechanic spends in the cold, the more reliable the operation.
Spiral freezers
A separate class of cold chain equipment is the spiral freezer, where the belt rises along a spiral inside an insulated chamber. Here the belt requirements are the strictest: it must not only withstand -40 °C but also bend in the lateral plane without deforming. For such units we use special modular belts with radius travel or stainless steel mesh belts with side flexing.
A critical spiral parameter is belt tension. In the cold the material contracts, and the tension set in a warm workshop may become insufficient in the working regime — the belt slips on the drive drum. So we install an automatic tensioning system that compensates for thermal shrinkage. Without it the spiral either slips or, conversely, over-tightens the belt and tears the module fasteners.
Design solutions for the cold
When designing a conveyor for a refrigerated facility, we build in several solutions:
- AISI 304 stainless frame instead of painted steel — condensation leaves a coating no chance.
- Open construction without cavities where ice accumulates.
- A 20–25% drive power reserve in case of icing and increased friction.
- A defrost system for continuously running tunnels.
For more on cooling lines, see the articles tagged freezing and the material on conveyor transport.
Energy efficiency of a refrigerated line
In the cold chain, energy is the main cost item: refrigeration equipment runs around the clock. A conveyor affects this bill indirectly but tangibly. Every extra kilowatt consumed by the drive in the freezing chamber turns into heat that the refrigeration unit must compensate — in effect every unit of “hot” energy is paid for twice.
So in the cold chain we are especially careful with the drive: an energy-efficient IE3–IE4 class gear motor, a converter for operation at optimal speed, minimised route friction. A remote drive outside the cold zone is not only more reliable but also does not heat the chamber. Fine decisions at the conveyor level deliver savings that, on the annual scale of a cold store, are measured in noticeable sums.
Conclusion
A cold chain conveyor is not an ordinary line moved into the cold but a separate engineering solution: a frost-resistant belt, synthetic lubricant, a stainless frame and a drive power reserve. A material mistake here turns into a failure mid-season. Planning a freezing line or a cold store? Get in touch — we’ll design a conveyor for your temperature regime.
