REFRIGERATION OF FISH 



601 



scoops pulled out, leaving- the fish in the cans arranged in an orderly 

 manner. In this position the fish in the bottom of the can are under 

 pressure from those above. This has the effect of reducing the 

 space occupied by the fish, with consequent saving of storage space, 

 and also secures the good contact with the can necessary for rapid 

 freezing. It has the disadvantage, however, of distorting the shape 

 of the fish. 



When the frame of cans is filled with fish, it is lifted, by an electric 

 hoist that moves on rails over the freezing tank. This is a tank 

 that resembles in all essentials an ice-making tank. It may be pro- 

 vided with refrigerating coils or an external shell cooler for refrig- 

 erating the brine, the brine being kept in motion among the cans by 

 an agitator. The frame of cans is lowered into the brine so that 



Fio. 3C. — Petersen's method of freezing. The fish emerge from the glazing tank 

 into a cold room, where the glaze sets and the cakes are boxed. Courtesy, Bay 

 City Freezer 



the open ends project above the brine level. A hatch lid covers 

 the can. 



As calcium chloride brine is used, the temperature may be very 

 low, with consequent rapid freezing. Peterson maintains a tempera- 

 ture as low as 25° or 30° F. below zero, but as brine is not in contact 

 with the fish any suitable temperature may be used. Cakes 4 inches 

 thick, in brine at 20° to 25° F. below zero, freeze in about 2 1 /o hours. 

 If allowance is made for time of dumping, glazing, and interruptions, 

 8 freezing cycles may be made in 24 hours, each frame of cans hold- 

 ing about 250 pounds. The capacity of a freezer is measured, of 

 course, by the number of cans the tank will accommodate. 



When the fish are frozen the hatch lid is taken off, the hoist 

 attached, and the frame of cans pulled out. To prevent any drip 

 of brine to the floor, with possible entrance into the fish cans in 

 the tank, a pan, mounted to roll on rails over the tank, is brought 



