A patent for a plate freezer innovation was awarded to Bruce Nelson, president of Colmac Coil, Colville, Wash.
According to the patent application, traditional direct-contact plate freezer designs have had common reoccurring deficiencies that result in potential health hazards. To counteract the nonuniform distribution of liquid refrigerant in traditional plate freezers, increased levels of refrigerant often are used. This creates a health hazard if the refrigerant is leaked. The most common instance of refrigerant leakage occurs at the connection of the refrigerant conduit to the common intake and suction manifolds. Because the threaded connections are stainless steel, and the freezer plates are aluminum, there is a difference in the linear coefficient of thermal expansion, resulting in leaks over repeated freezing cycles.
Nelson’s design resolves these concerns and helps ensure a safe environment for workers near the freezers. By using a wicking structure and internal passageways, the uniformity of the refrigerant flow is increased, thus reducing health hazards should a leak occur. A bimetallic coupling used at the connection of the conduit to the freezing plates eliminates the risk of refrigerant leaks over multiple freezing cycles.