336 MARINE PRODUCTS OF COMMERCE 



If frozen in cakes or blocks, the fish are pressed out of shape and individual fish 

 cannot be separated from the cake without damage to the skin. If the fish are 

 frozen in brine, some salt may penetrate the tissues and the blood may be dis- 

 colored by the action of the salt. 



Layout, Construction, and Mechanical Equipment of Fish-Freezing Plants 



Fish-freezing plants, like almost any other class of plants for commercial opera- 

 tions, have equipment w^hich varies from the simple, crude, and inexpensive to 

 the large, complex, and costly. Most of them are on or near the water; many are 

 not exclusively fish freezers, but take other perishables for cold storage. Most 

 of them make ice, whereas some do a public fish-warehousing business and others 

 are entirely private. The public houses freeze and store fish for customers at a 

 fixed charge and the private houses own the holdings outright, buying fish in the 

 producing season and selling in the consuming season. Practices in freezing and 

 storing fish are not at all standardized as more or less natural, but nevertheless 

 great, differences appear in different regions and with different species of fish. 



Construction and Location of Freezers. Many freezers are built on piers so as 

 to be readily accessible by boats, which receive cmshed ice through chutes 

 while unloading fish. The better types of freezers are constructed of steel and 

 concrete, with an envelope of corkboard for insulation. Many are of frame con- 

 struction, with sawdust, felt, or other cheaper material for insulating purposes. 

 Usually the machinery, because of its weight and vibration, is located on the 

 ground floor or in the basement. The receiving, washing, and panning rooms are 

 usually on the ground floor, but are sometimes on the top floor. The sharp freezers 

 are usually on the first or second floor if the fish are received on the first floor, but 

 in one large freezer in New York the fish are received on the ground floor and 

 are washed, panned, and sent to the top floor by continuous chain elevator. In a 

 plant in Portland, Maine the fish are received on the top floor and conveyed 

 through hatches to the sharp freezers on the floor immediately below. More com- 

 monly, however, the sharp freezers are on the first or second floor. 



The sharp freezers are usually small rooms, having a capacity of from 15,000 

 to 40,000 pounds, though in some plants larger rooms are more satisfactory. The 

 smaller rooms are usually much longer than they are wide, and are equipped 

 with shelving made of steel pipe through which the brine or ammonia circulates. 

 On these pipes the fish are placed to freeze. The large rooms, especially where 

 brine is circulated, permit loading without excessive elevation of temperature, 

 and consequently with quicker freezing, while the small rooms permit loading 

 without interference with the progress of freezing of lots in other rooms. 



The glazing room is usually conveniently located at some point on the route 

 from sharp freezer to storage. When there is no definite room for this purpose, a 

 corridor is often used; sometimes movable glazing tanks are employed in the 

 storage rooms. More often, however, a glazing tank is permanently built in at a 

 convenient place. 



The storage rooms are usually large— much larger than the sharp freezers. The 

 refrig^ating pipe coils are arranged on the side walls and ceilings. Slatwork is 

 sometimes laid 4 to 6 inches from the floors and side walls to permit circulation 

 of air. 



Thermometers should be placed in all cold rooms at places where they are sure 



