Stalam has developed a rapid in-line defrosting equipment based on the Radio Frequency technology that allows a significant reduction of drip losses and minimises product deterioration due to bacterial growth. This fast, uniform and controlled heating method offers great flexibility in production scheduling and is the ideal solution for many tempering, softening and defrosting processes.
The product is placed on the machine’s conveyor belt and is transferred continuously through the RF unit (tunnel) passing between upper and lower metallic plates. These plates (also called electrodes) form an electrical capacitor and the product in between the plates becomes the dielectric element of that capacitor. The electrode plates are connected to a radio frequency generator oscillating at a frequency of several million cycles per second. When the RF generator applies high frequency alternating voltage between the capacitor plates, the dipolar water molecules of the frozen product will vibrate and rotate attempting to align themselves according to the fast changing opposite plates polarities.
This phenomenon causes intermolecular friction, which will in turn generate heat rapidly and uniformly within the whole product mass regardless of its size, weight, shape and thermal conductivity. The amount of heat generated inside the product and the defrosting time are accurately controlled through the voltage applied on the electrode plates and the speed of the conveyor belt.