474 



MARINE PRODUCTS OF COMMERCE 



BUCKET ELEVATOR 



RAW FISH 



STEAM COOKER 



SETTLING TANK SYSTEM 

 OIL RECOVERY 



CO NTINUOUS 



SCREW 



PRESS 



SCREW jttfi'^ 





IMPRESS CAKE 



ESS 



LIQUOR 



V^ 



TO 

 r- FINISHED 

 OIL 

 STORAGE 



TO STICKWkTER PLANT 



OR SEWER 

 HEATING 

 i TANKS 



CENTRIFUGE 



SYSTEM-OIL 



OEODORIZER 



TO SEWER 



MILL 



GROUND MEAU 



Fig. 22-3. Flow sheet for a typical fish reduction plant ( wet method ) . 



hold and deposited into some type of weighing mechanism. Within the last 3 years 

 a centrifugal pump arrangement has been developed for pumping the fish from 

 the hold of the vessel. This method of unloading is described more fully on 

 pages 438 and 439. 



The fish are mechanically conveyed from the weighing station to the plant and 

 discharged into a large storage bin or "raw box." These bins are usually about 

 10 feet deep, but their length and breadth vary according to the capacity of the 

 plant and the number and size of the cookers employed. The floor of the bin slants 

 from both sides toward the middle where a screw-type conveyor is located. The 

 conveyor is placed in a closed box with a cover which may be removed in sections 

 as the bin is emptied. This screw conveys the fish from the "raw box" into the 

 hopper, which feeds the continuous cooker. Its speed is regulated so that the fish 

 will be fed into the hopper just as rapidly as they are passed through the cooker. 



Continuous Cooker. Since it is desirable to cook the fish as soon as they are 

 taken from the water, cooking is usually begun simultaneously with unloading. 

 Stale fish putrefy quickly and are much more difficult to handle. Cooking breaks 

 the fat cells so that oil is easily obtained when the fish are pressed. 



The continuous fish cooker in general use today consists essentially of a station- 

 ary horizontal steel plate cylinder, from 16 to 30 inches in diameter and from 20 

 to 40 feet in length; this is fitted with an intake hopper at one end and a special 

 discharge opening at the other. The lower portion of the cylinder is usually pro- 

 vided with several longitudinal rows of steam inlets or nozzles so placed that jets 

 of live steam, under 5- to 10-pounds pressure, can be forced directly into the 

 mass of fish moving slowly over the inner surface of the cooker shell. A hollow 

 shaft, rotated by means of suitable gearing and supported in the two heads of the 

 cooker, extends through the longitudinal center-line of the cylinder. Frequently, 



