In the cold chain, the thermal shocks between air masses at −15°F and the outside at above-freezing temperatures, for example, 45°F, causes icing-up which hinders operation and prematurely wears traditional roller flexible doors, as the "cold" side has a tendency to stick to the "warm" side on each opening.
The curtain of this high-speed door does not roll up onto itself, it can therefore receive any thickness of double flexible insulator accommodating a double captive air blanket trapped between three flexible PVC walls increasing the thermal resistance up to 4 Btu/ft2h°F. To withstand the high pressure differences in cold rooms, it is strengthened at regular intervals from top to bottom of the opening by stiffeners which tension it evenly in closed position to provide excellent sealing and distribute the pressure over the whole frame uniformly.
Each time it is opened, the folding technology overcomes any friction in the slides for much greater reliability, and removes the need for a rigid bar at the bottom or a system holding the curtain captive in the side guides. Directly responsive, it opens as late as possible and closes after the vehicle/individual has passed through, at the same speed with no contact risk, to reduce air exchanges.
The motor drive system, which is adapted to working in an extremely cold environment, is directly connected to limit the number of moving parts. The frame is protected against ice forming by a low-emissivity de-icing system and may be made of multi-composite materials or steel:
Cold storage door with multi-composite frame
This structure is built from composite materials which form a natural thermal barrier and are more corrosion-resistant than stainless steel.
Cold storage door with steel frame
This cold storage high-speed door uses a self-supporting steel frame to reduce loading on the support wall. Its lower overall lateral dimensions save space.