350 MARINE PRODUCTS OF COMMERCE 



The "Birdseye" multiplate freezer was devised primarily for the freezing of 

 foods packaged in rectangular paperboard packages. It is extensively used for 

 the freezing of packaged fillets, steaks, and small fish. It consists of a number 

 of superimposed refrigerated hollow metal plates, so actuated hydraulically that 

 they will open to receive products between them and will close on the products 

 with any desired pressure. The entire freezing apparatus, with the exception of the 

 refrigerating unit, is enclosed in an insulated cabinet. As a rule the smaller 

 freezers, 6 stations and less, are self-contained and have compressor, compressor 

 motor, condenser, hydraulic lift cylinder, hydraulic oil tank, and pressure pump 

 located directly underneath the insulated freezing chamber. The larger machines 

 have separate refrigerating systems. 



The plates of the earlier multiplate freezers were constructed of rolled 

 aluminum alloy and provided with sinuous passages. Some of the more recent 

 models have stainless steel plates which are much thinner than those of aluminum. 

 This has the advantage that many more plates can be put in a freezer of any given 

 height. A rubber hose is connected to a header which feeds each plate with 

 the ammonia, "Freon," or brine used as the refrigerant. The other end of the 

 plate is also connected by a rubber hose to another header which returns the 

 ammonia or brine to the surge drum (in the case of ammonia) or to the re- 

 frigerating machine. 



Most of the multiplate freezers have a hydraulically operated cylinder located 

 under the bottom plate. As pressure is applied on the under side of the bottom 

 plate, it lifts its load until it meets the second plate, which in turn is raised with 

 its load, and so on up. 



Before the packaged product to be frozen is placed in the machine, the plates 

 are cooled to about — 28° F (— 33.3°C). The packaged products are placed 

 on thin metal trays, which in turn are loaded into the freezer. Sticks of wood, 

 as long as the plates and slightly less in height than the thickness of the packages 

 being frozen, are placed on each side of the machine between each pair of 

 plates to prevent crushing of the packages. The cabinet doors are then closed 

 and the hydraulic pressure is applied to raise the plates and exert pressure upon 

 the packages. As a rule the product is left in the freezer until the center of the 

 packages reaches about 0° F. Of course the freezing time varies with both the 

 thickness of the packages and the kind of food being frozen. Packages 

 of fish fillets, 2 inches in thickness, require approximately 90 minutes to freeze. 



The "Birdseye" multiplate freezer has a great capacity per square foot of 

 floor space, far greater in this respect than the original "Birdseye" double-belt 

 freezer. Further, the self-contained units are portable since they require only 

 electric current and water connections for their operation. 



The Jackstone Contact Freezer. Amerio Manufacturing Incorporated makes a 

 multiplate freezer, designed by A. J. Stone, which closely resembles the "Birdseye" 

 multiplate freezer. It consists of 16 Dole "vacuum" plates superimposed one over 

 the other so as to give 15 freezing stations. The maximum opening of the plates 

 is 3 inches; consequently, packages or products thicker than 3 inches cannot be 

 frozen between the plates. In the closed position the minimum opening is 1 inch 

 and wrapped fillets or packages thinner than this cannot be frozen. 



The refrigerant system used is the "flooded" type. The surge drum is located 

 on top of the freezing cabinet. The freezer is supplied ready to be hooked up to 



